Two-Terminal Lithium-Mediated Artificial Synapses with Enhanced Weight Modulation for Feasible Hardware Neural Networks
Corresponding Author: Ho Won Jang
Nano-Micro Letters,
Vol. 15 (2023), Article Number: 69
Abstract
Recently, artificial synapses involving an electrochemical reaction of Li-ion have been attributed to have remarkable synaptic properties. Three-terminal synaptic transistors utilizing Li-ion intercalation exhibits reliable synaptic characteristics by exploiting the advantage of non-distributed weight updates owing to stable ion migrations. However, the three-terminal configurations with large and complex structures impede the crossbar array implementation required for hardware neuromorphic systems. Meanwhile, achieving adequate synaptic performances through effective Li-ion intercalation in vertical two-terminal synaptic devices for array integration remains challenging. Here, two-terminal Au/LixCoO2/Pt artificial synapses are proposed with the potential for practical implementation of hardware neural networks. The Au/LixCoO2/Pt devices demonstrated extraordinary neuromorphic behaviors based on a progressive dearth of Li in LixCoO2 films. The intercalation and deintercalation of Li-ion inside the films are precisely controlled over the weight control spike, resulting in improved weight control functionality. Various types of synaptic plasticity were imitated and assessed in terms of key factors such as nonlinearity, symmetricity, and dynamic range. Notably, the LixCoO2-based neuromorphic system outperformed three-terminal synaptic transistors in simulations of convolutional neural networks and multilayer perceptrons due to the high linearity and low programming error. These impressive performances suggest the vertical two-terminal Au/LixCoO2/Pt artificial synapses as promising candidates for hardware neural networks.
Highlights:
1 The Li-mediated artificial synapses with a vertical two-terminal configuration capable of various synaptic behaviors, including bio-plausible synaptic plasticity, were successfully demonstrated for the first time and thoroughly explored
2 Synaptic characteristics based on the progressive dearth of Li in LixCo2 films are precisely controlled over the weight control spike, achieving extraordinary weight control functionality.
3 In artificial neural network simulation, LixCoO2-based neuromorphic system showed excellent accuracy comparable to the theoretical maximum due to the low nonlinearity and programming error, suggesting feasibility of hardware neural network implementation.
Keywords
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- S. LaValle, E. Lesser, R. Shockley, M.S. Hopkins, N. Kruschwitz, Big data, analytics and the path from insights to value. MIT Sloan Manag. Rev. 52, 21–32 (2011)
- D.J. Frank, R.H. Dennard, E. Nowak, P.M. Solomon, Y. Taur et al., Device scaling limits of Si MOSFETs and their application dependencies. Proc. IEEE 89, 259–288 (2001). https://doi.org/10.1109/5.915374
- M.M. Waldrop, The chips are down for Moore’s law. Nature 530, 144 (2016). https://doi.org/10.1038/530144a
- J. Backus, Can programming be liberated from the von Neumann style?: a functional style and its algebra of programs. Commun. ACM 21, 613–641 (1978). https://doi.org/10.1145/359576.359579
- Y. Zhang, P. Qu, Y. Ji, W. Zhang, G. Gao et al., A system hierarchy for brain-inspired computing. Nature 586, 378–384 (2020). https://doi.org/10.1038/s41586-020-2782-y
- B. Goertzel, Artificial general intelligence: concept, state of the art, and future prospects. J. Artif. Gen. Intell. 5, 1 (2014). https://doi.org/10.2478/jagi-2014-0001
- S. Yu, Neuro-inspired computing with emerging nonvolatile memorys. Proc. IEEE 106, 260–285 (2018). https://doi.org/10.1109/JPROC.2018.2790840
- C. Mead, Neuromorphic electronic systems. Proc. IEEE 78, 1629–1636 (1990). https://doi.org/10.1109/5.58356
- P. Gkoupidenis, D.A. Koutsouras, G.G. Malliaras, Neuromorphic device architectures with global connectivity through electrolyte gating. Nat. Commun. 8, 15448 (2017). https://doi.org/10.1038/ncomms15448
- S. Ambrogio, P. Narayanan, H. Tsai, R.M. Shelby, I. Boybat et al., Equivalent-accuracy accelerated neural-network training using analogue memory. Nature 558, 60–67 (2018). https://doi.org/10.1038/s41586-018-0180-5
- J.C. Magee, C. Grienberger, Synaptic plasticity forms and functions. Annu. Rev. Neurosci. 43, 95–117 (2020). https://doi.org/10.1146/annurev-neuro-090919-022842
- A. Citri, R.C. Malenka, Synaptic plasticity: multiple forms, functions, and mechanisms. Neuropsychopharmacology 33, 18–41 (2008). https://doi.org/10.1038/sj.npp.1301559
- V.M. Ho, J.A. Lee, K.C. Martin, The cell biology of synaptic plasticity. Science 334(6056), 623–628 (2011). https://doi.org/10.1126/science.1209236
- G.W. Burr, P. Narayanan, R.M. Shelby, S. Sidler, I. Boybat et al., Large-scale neural networks implemented with non-volatile memory as the synaptic weight element: comparative performance analysis (accuracy, speed, and power). In: 2015 IEEE Int. Electron Devices Meet, Washington, DC, USA (2015). https://doi.org/10.1109/IEDM.2015.7409625
- K.C. Kwon, J.H. Baek, K. Hong, S.Y. Kim, H.W. Jang, Memristive devices based on two-dimensional transition metal chalcogenides for neuromorphic computing. Nano-Micro Lett. 14, 58 (2022). https://doi.org/10.1007/s40820-021-00784-3
- S.H. Choi, S.O. Park, S. Seo, S. Choi, Reliable multilevel memristive neuromorphic devices based on amorphous matrix via quasi-1D filament confinement and buffer layer. Sci. Adv. 8, eabj7866 (2022). https://doi.org/10.1126/sciadv.abj7866
- W. Xu, S.Y. Min, H. Hwang, T.W. Lee, Organic core-sheath nanowire artificial synapses with femtojoule energy consumption. Sci. Adv. 2, e1501326 (2022). https://doi.org/10.1126/sciadv.1501326
- K.J. Kwak, D.E. Lee, S.J. Kim, H.W. Jang, Halide perovskites for memristive data storage and artificial synapses. J. Phys. Chem. Lett. 12, 8999–9010 (2021). https://doi.org/10.1021/acs.jpclett.1c02332
- S.G. Kim, Q.V. Le, J.S. Han, H. Kim, M.J. Choi et al., Dual-phase all-inorganic cesium halide perovskites for conducting-bridge memory-based artificial synapses. Adv. Funct. Mater. 29(49), 1906696 (2019). https://doi.org/10.1002/adfm.201906686
- S. Yu, Y. Wu, R. Jeyasingh, D. Kuzum, H.S.P. Wong, An electronic synapse device based on metal oxide resistive switching memory for neuromorphic computation. IEEE Trans. Electron Devices 58, 2729–2737 (2011). https://doi.org/10.1109/TED.2011.2147791
- S.J. Kim, T.H. Lee, J.M. Yang, J.W. Yang, Y.J. Lee et al., Vertically aligned two-dimensional halide perovskites for reliably operable artificial synapses. Mater. Today 52, 19–30 (2022). https://doi.org/10.1016/j.mattod.2021.10.035
- K.J. Kwak, J.H. Baek, D.E. Lee, I. Im, J. Kim et al., Ambient stable all inorganic CsCu2I3 artificial synapses for neurocomputing. Nano Lett. 22(14), 6010–6017 (2022). https://doi.org/10.1021/acs.nanolett.2c01272
- F. Jiao, B. Chen, K. Ding, K. Li, L. Wang et al., Monatomic 2D phase-change memory for precise neuromorphic computing. Appl. Mater. Today 20, 100641 (2020). https://doi.org/10.1016/j.apmt.2020.100641
- X. Mou, J. Tang, Y. Lyu, Q. Zhang, S. Yang et al., Analog memristive synapse based on topotactic phase transition for high-performance neuromorphic computing and neural network pruning. Sci. Adv. 7(29), eabh0648 (2022). https://doi.org/10.1126/sciadv.abh0648
- D. Ielmini, H.S.P. Wong, In-memory computing with resistive switching devices. Nat. Electron. 1, 333–343 (2018). https://doi.org/10.1038/s41928-018-0092-2
- J.J. Yang, D.B. Strukov, D.R. Stewart, Memristive devices for computing. Nat. Nanotechnol. 8, 13–24 (2013). https://doi.org/10.1038/nnano.2012.240
- I.H. Im, S.J. Kim, H.W. Jang, Memristive devices for new computing paradigms. Adv. Intell. Syst. 2, 2000105 (2020). https://doi.org/10.1002/aisy.202000105
- S. Seo, B.S. Kang, J.J. Lee, H.J. Ryu, S. Kim et al., Artificial van der Waals hybrid synapse and its application to acoustic pattern recognition. Nat. Commun. 11, 3936 (2020). https://doi.org/10.1038/s41467-020-17849-3
- Y. Choi, S. Oh, C. Qian, J.H. Park, J.H. Cho, Vertical organic synapse expandable to 3D crossbar array. Nat. Commun. 11, 4595 (2020). https://doi.org/10.1038/s41467-020-17850-w
- G. Li, D. Xie, H. Zhong, Z. Zhang, X. Fu et al., Photo-induced non-volatile VO2 phase transition for neuromorphic ultraviolet sensors. Nat. Commun. 13, 1729 (2022). https://doi.org/10.1038/s41467-022-29456-5
- S. Dai, Y. Zhao, Y. Wang, J. Zhang, L. Fang et al., Recent advances in transistor-based artificial synapses. Adv. Funct. Mater. 29(42), 1903700 (2019). https://doi.org/10.1002/adfm.201903700
- J. Zhu, Y. Yang, R. Jia, Z. Liang, W. Zhu et al., Ion gated synaptic transistors based on 2D van der Waals crystals with tunable diffusive dynamics. Adv. Mater. 30(21), 1800195 (2018). https://doi.org/10.1002/adma.201800195
- C.S. Yang, D.S. Shang, N. Liu, E.J. Fuller, S. Agrawal et al., All-solid-state synaptic transistor with ultralow conductance for neuromorphic computing. Adv. Funct. Mater. 28(42), 1804170 (2018). https://doi.org/10.1002/adfm.201804170
- E.J. Fuller, F. El Gabaly, F. Léonard, S. Agarwal, S.J. Plimpton et al., Li-ion synaptic transistor for low power analog computing. Adv. Mater. 29(4), 1604310 (2017). https://doi.org/10.1002/adma.201604310
- R.D. Nikam, M. Kwak, J. Lee, K.G. Rajput, W. Banerjee et al., Near ideal synaptic functionalities in Li ion synaptic transistor using Li3POxSex electrolyte with high ionic conductivity. Sci. Rep. 9, 18883 (2019). https://doi.org/10.1038/s41598-019-55310-8
- R.D. Nikam, M. Kwak, J. Lee, K.G. Rajput, H. Hwang, Controlled ionic tunneling in lithium nanoionic synaptic transistor through atomically thin graphene layer for neuromorphic computing. Adv. Electron. Mater. 6(2), 1901100 (2020). https://doi.org/10.1002/aelm.201901100
- P.S. Ioannou, E. Kyriakides, O. Schneegans, J. Giapintzakis, Evidence of biorealistic synaptic behavior in diffusive Li-based two-terminal resistive switching devices. Sci. Rep. 10, 8711 (2020). https://doi.org/10.1038/s41598-020-65237-0
- C. Lee, J. Lee, M. Kim, J. Woo, S.M. Koo et al., Two-terminal structured synaptic device using ionic electrochemical reaction mechanism for neuromorphic system. IEEE Electron Device Lett. 40, 546–549 (2019). https://doi.org/10.1109/LED.2019.2897777
- Y. Choi, C. Lee, M. Kim, Y. Song, H. Hwang et al., Structural engineering of Li-based electronic synapse for high reliability. IEEE Electron Device Lett. 40, 1992–1995 (2019). https://doi.org/10.1109/LED.2019.2950202
- C.Y. Lin, J. Chen, P.H. Chen, T.C. Chang, Y. Wu et al., Adaptive synaptic memory via lithium ion modulation in RRAM devices. Small 16(42), 2003964 (2020). https://doi.org/10.1002/smll.202003964
- K. Ozawa, Lithium-ion rechargeable batteries with LiCoO2 and carbon electrodes: the LiCoO2/C system. Solid State Ionics 69, 212–221 (1994). https://doi.org/10.1016/0167-2738(94)90411-1
- J. Cho, Y.J. Kim, B. Park, Novel LiCoO2 cathode material with Al2O3 coating for a Li ion cell. Chem. Mater. 12, 3788–3791 (2000). https://doi.org/10.1021/cm000511k
- E. Antolini, LiCoO2: formation, structure, lithium and oxygen nonstoichiometry, electrochemical behaviour and transport properties. Solid State Ionics 170, 159–171 (2004). https://doi.org/10.1016/j.ssi.2004.04.003
- Y. Lyu, X. Wu, K. Wang, Z. Feng, T. Cheng et al., An overview on the advances of LiCoO2 cathodes for lithium-ion batteries. Adv. Energy Mater. 11(2), 2000982 (2021). https://doi.org/10.1002/aenm.202000982
- S. Levasseur, M. Ménétrier, E. Suard, C. Delmas, Evidence for structural defects in non-stoichiometric HT-LiCoO2: electrochemical, electronic properties and 7Li NMR studies. Solid State Ionics 128, 11–24 (2000). https://doi.org/10.1016/S0167-2738(99)00335-5
- M. Shibuya, T. Nishina, T. Matsue, I. Uchida, In situ conductivity measurements of LiCoO2 film during lithium insertion/extraction by using interdigitated microarray electrodes. J. Electrochem. Soc. 143, 3157–3160 (1996). https://doi.org/10.1149/1.1837180
- Y. Takahashi, Y. Gotoh, J. Akimoto, S. Mizuta, K. Tokiwa et al., Anisotropic electrical conductivity in LiCoO2 single crystal. J. Solid State Chem. 164, 1–4 (2002). https://doi.org/10.1006/jssc.2001.9459
- S. Yamakawa, H. Yamasaki, T. Koyama, R. Asahi, Numerical study of Li diffusion in polycrystalline LiCoO2. J. Power Sources 223, 199–205 (2013). https://doi.org/10.1016/j.jpowsour.2012.09.055
- P.J. Bouwman, B.A. Boukamp, H.J.M. Bouwmeester, P.H.L. Notten, Influence of diffusion plane orientation on electrochemical properties of thin film LiCoO2 electrodes. J. Electrochem. Soc. 149, A699 (2002). https://doi.org/10.1149/1.1471543
- H.S. Lee, C. Park, C.S. Oh, H.S. Lee, H.I. Seo et al., Atomic structure and defect energetics of LiCoO2 grain boundary. Mater. Res. Bull. 82, 81–86 (2016). https://doi.org/10.1016/j.materresbull.2016.04.017
- H. Moriwake, A. Kuwabara, C.A.J. Fisher, R. Huang, T. Hitosugi et al., First-principles calculations of lithium-ion migration at a coherent grain boundary in a cathode material, LiCoO2. Adv. Mater. 25(4), 618–622 (2013). https://doi.org/10.1002/adma.201202805
- H. Xia, L. Lu, G. Ceder, Li diffusion in LiCoO2 thin films prepared by pulsed laser deposition. J. Power Sources 159, 1422–1427 (2006). https://doi.org/10.1016/j.jpowsour.2005.12.012
- P.J. Bouwman, B.A. Boukamp, H.J.M. Bouwmeester, P.H.L. Notten, Structure-related intercalation behaviour of LiCoO2 films. Solid State Ionics 152–153, 181–188 (2002). https://doi.org/10.1016/S0167-2738(02)00298-9
- H. Xia, L. Lu, Texture effect on the electrochemical properties of LiCoO2 thin films prepared by PLD. Electrochim. Acta 52, 7014–7021 (2007). https://doi.org/10.1016/j.electActa2007.05.019
- P. Bach, M. Stratmann, I. Valencia-Jaime, A.H. Romero, F.U. Renner, Lithiation and delithiation mechanisms of gold thin film model anodes for lithium ion batteries: electrochemical characterization. Electrochim. Acta 164, 81–89 (2015). https://doi.org/10.1016/j.electActa2015.02.184
- P. Bach, I. Valencia-Jaime, U. Rütt, O. Gutowski, A.H. Romero et al., Electrochemical lithiation cycles of gold anodes observed by in situ high-energy X-ray diffraction. Chem. Mater. 28, 2941–2948 (2016). https://doi.org/10.1021/acs.chemmater.5b04719
- A.D. Pelton, The Au−Li (Gold–Lithium) system. Bull. Alloy Phase Diagr. 7, 228–231 (1986). https://doi.org/10.1007/BF02868994
- R.C. Atkinson, R.M. Shiffrin, Human memory: a proposed system and its control processes. Psychol. Learn. Motiv. 2, 89–195 (1968). https://doi.org/10.1016/S0079-7421(08)60422-3
- D.V. Buonomano, Decoding temporal information: a model based on short-term synaptic plasticity. J. Neurosci. 20, 1129–1141 (2000). https://doi.org/10.1523/JNEUROSCI.20-03-01129.2000
- P.E. Schulz, E.P. Cook, D. Johnston, Changes in paired-pulse facilitation suggest presynaptic involvement in long-term potentiation. J. Neurosci. 14, 5325–5337 (1994). https://doi.org/10.1523/JNEUROSCI.14-09-05325.1994
- D.E. Feldman, Timing-based LTP and LTD at vertical inputs to layer II/III pyramidal cells in rat barrel cortex. Neuron 27, 45–56 (2000). https://doi.org/10.1016/S0896-6273(00)00008-8
- G. Bi, M. Poo, Synaptic modifications in cultured hippocampal neurons: dependence on spike timing, synaptic strength, and postsynaptic cell type. J. Neurosci. 18, 10464–10472 (1998). https://doi.org/10.1523/JNEUROSCI.18-24-10464.1998
- H. Markram, J. Lübke, M. Frotscher, B. Sakmann, Regulation of synaptic efficacy by coincidence of postsynaptic APs and EPSPs. Science 275(5297), 213–215 (1997). https://doi.org/10.1126/science.275.5297.213
- R.S. Zucker, W.G. Regehr, Short-term synaptic plasticity. Annu. Rev. Physiol. 64, 355–405 (2002). https://doi.org/10.1146/annurev.physiol.64.092501.114547
- L. Dahéron, R. Dedryvère, H. Martinez, M. Ménétrier, C. Denage et al., Electron transfer mechanisms upon lithium deintercalation from LiCoO2 to CoO2 investigated by XPS. Chem. Mater. 20, 583–590 (2008). https://doi.org/10.1021/cm702546s
- J.C. Dupin, D. Gonbeau, H. Benqlilou-Moudden, P. Vinatier, A. Levasseur, XPS analysis of new lithium cobalt oxide thin-films before and after lithium deintercalation. Thin Solid Films 384, 23–32 (2001). https://doi.org/10.1016/S0040-6090(00)01802-2
- C. Julien, Local cationic environment in lithium nickel–cobalt oxides used as cathode materials for lithium batteries. Solid State Ionics 136, 887–896 (2000). https://doi.org/10.1016/S0167-2738(00)00503-8
- M. Inaba, Y. Iriyama, Z. Ogumi, Y. Todzuka, A. Tasaka, Raman study of layered rock-salt LiCoO2 and its electrochemical lithium deintercalation. J. Raman Spectrosc. 28, 613–617 (1997). https://doi.org/10.1002/(SICI)1097-4555(199708)28:8%3c613::AID-JRS138%3e3.0.CO;2-T
- Y. LeCun, C. Cortes, The MNISTdatabase of handwritten digit images for machine learning research. (2010). http://yann.lecun.com/exdb/mnist
- A. Krizhevsky, V. Nair, G. Hinton, CIFAR-10 (Canadian Institute for Advanced Research). http://www.cs.toronto.edu/~kriz/cifar.html
- A. Krizhevsky, V. Nair, G. Hinton, CIFAR-100 (Canadian Institute for Advanced Research). http://www.cs.toronto.edu/~kriz/cifar.html
- J. Deng, W. Dong, R. Socher, L.J. Li, K. Li et al., ImageNet: a large-scale hierarchical image database. In: 2009 IEEE Conference on Computer Vision Pattern Recognition, Miami, FL, USA, (2009). https://doi.org/10.1109/CVPR.2009.5206848
- T.P. Xiao, C.H. Bennett, B. Feinberg, M.J. Marinella, S. Agarwal, CrossSim: accuracy simulation of analog in-memory computing. https://github.com/sandialabs/cross-sim
- X. Xu, Y. Ding, S.X. Hu, M. Niemier, J. Cong et al., Scaling for edge inference of deep neural networks. Nat. Electron. 1, 216–222 (2018). https://doi.org/10.1038/s41928-018-0059-3
- S. Ruder, An overview of gradient descent optimization algorithms. ArXiv, 1609.04747 (2016). https://doi.org/10.48550/arXiv.1609.04747
References
S. LaValle, E. Lesser, R. Shockley, M.S. Hopkins, N. Kruschwitz, Big data, analytics and the path from insights to value. MIT Sloan Manag. Rev. 52, 21–32 (2011)
D.J. Frank, R.H. Dennard, E. Nowak, P.M. Solomon, Y. Taur et al., Device scaling limits of Si MOSFETs and their application dependencies. Proc. IEEE 89, 259–288 (2001). https://doi.org/10.1109/5.915374
M.M. Waldrop, The chips are down for Moore’s law. Nature 530, 144 (2016). https://doi.org/10.1038/530144a
J. Backus, Can programming be liberated from the von Neumann style?: a functional style and its algebra of programs. Commun. ACM 21, 613–641 (1978). https://doi.org/10.1145/359576.359579
Y. Zhang, P. Qu, Y. Ji, W. Zhang, G. Gao et al., A system hierarchy for brain-inspired computing. Nature 586, 378–384 (2020). https://doi.org/10.1038/s41586-020-2782-y
B. Goertzel, Artificial general intelligence: concept, state of the art, and future prospects. J. Artif. Gen. Intell. 5, 1 (2014). https://doi.org/10.2478/jagi-2014-0001
S. Yu, Neuro-inspired computing with emerging nonvolatile memorys. Proc. IEEE 106, 260–285 (2018). https://doi.org/10.1109/JPROC.2018.2790840
C. Mead, Neuromorphic electronic systems. Proc. IEEE 78, 1629–1636 (1990). https://doi.org/10.1109/5.58356
P. Gkoupidenis, D.A. Koutsouras, G.G. Malliaras, Neuromorphic device architectures with global connectivity through electrolyte gating. Nat. Commun. 8, 15448 (2017). https://doi.org/10.1038/ncomms15448
S. Ambrogio, P. Narayanan, H. Tsai, R.M. Shelby, I. Boybat et al., Equivalent-accuracy accelerated neural-network training using analogue memory. Nature 558, 60–67 (2018). https://doi.org/10.1038/s41586-018-0180-5
J.C. Magee, C. Grienberger, Synaptic plasticity forms and functions. Annu. Rev. Neurosci. 43, 95–117 (2020). https://doi.org/10.1146/annurev-neuro-090919-022842
A. Citri, R.C. Malenka, Synaptic plasticity: multiple forms, functions, and mechanisms. Neuropsychopharmacology 33, 18–41 (2008). https://doi.org/10.1038/sj.npp.1301559
V.M. Ho, J.A. Lee, K.C. Martin, The cell biology of synaptic plasticity. Science 334(6056), 623–628 (2011). https://doi.org/10.1126/science.1209236
G.W. Burr, P. Narayanan, R.M. Shelby, S. Sidler, I. Boybat et al., Large-scale neural networks implemented with non-volatile memory as the synaptic weight element: comparative performance analysis (accuracy, speed, and power). In: 2015 IEEE Int. Electron Devices Meet, Washington, DC, USA (2015). https://doi.org/10.1109/IEDM.2015.7409625
K.C. Kwon, J.H. Baek, K. Hong, S.Y. Kim, H.W. Jang, Memristive devices based on two-dimensional transition metal chalcogenides for neuromorphic computing. Nano-Micro Lett. 14, 58 (2022). https://doi.org/10.1007/s40820-021-00784-3
S.H. Choi, S.O. Park, S. Seo, S. Choi, Reliable multilevel memristive neuromorphic devices based on amorphous matrix via quasi-1D filament confinement and buffer layer. Sci. Adv. 8, eabj7866 (2022). https://doi.org/10.1126/sciadv.abj7866
W. Xu, S.Y. Min, H. Hwang, T.W. Lee, Organic core-sheath nanowire artificial synapses with femtojoule energy consumption. Sci. Adv. 2, e1501326 (2022). https://doi.org/10.1126/sciadv.1501326
K.J. Kwak, D.E. Lee, S.J. Kim, H.W. Jang, Halide perovskites for memristive data storage and artificial synapses. J. Phys. Chem. Lett. 12, 8999–9010 (2021). https://doi.org/10.1021/acs.jpclett.1c02332
S.G. Kim, Q.V. Le, J.S. Han, H. Kim, M.J. Choi et al., Dual-phase all-inorganic cesium halide perovskites for conducting-bridge memory-based artificial synapses. Adv. Funct. Mater. 29(49), 1906696 (2019). https://doi.org/10.1002/adfm.201906686
S. Yu, Y. Wu, R. Jeyasingh, D. Kuzum, H.S.P. Wong, An electronic synapse device based on metal oxide resistive switching memory for neuromorphic computation. IEEE Trans. Electron Devices 58, 2729–2737 (2011). https://doi.org/10.1109/TED.2011.2147791
S.J. Kim, T.H. Lee, J.M. Yang, J.W. Yang, Y.J. Lee et al., Vertically aligned two-dimensional halide perovskites for reliably operable artificial synapses. Mater. Today 52, 19–30 (2022). https://doi.org/10.1016/j.mattod.2021.10.035
K.J. Kwak, J.H. Baek, D.E. Lee, I. Im, J. Kim et al., Ambient stable all inorganic CsCu2I3 artificial synapses for neurocomputing. Nano Lett. 22(14), 6010–6017 (2022). https://doi.org/10.1021/acs.nanolett.2c01272
F. Jiao, B. Chen, K. Ding, K. Li, L. Wang et al., Monatomic 2D phase-change memory for precise neuromorphic computing. Appl. Mater. Today 20, 100641 (2020). https://doi.org/10.1016/j.apmt.2020.100641
X. Mou, J. Tang, Y. Lyu, Q. Zhang, S. Yang et al., Analog memristive synapse based on topotactic phase transition for high-performance neuromorphic computing and neural network pruning. Sci. Adv. 7(29), eabh0648 (2022). https://doi.org/10.1126/sciadv.abh0648
D. Ielmini, H.S.P. Wong, In-memory computing with resistive switching devices. Nat. Electron. 1, 333–343 (2018). https://doi.org/10.1038/s41928-018-0092-2
J.J. Yang, D.B. Strukov, D.R. Stewart, Memristive devices for computing. Nat. Nanotechnol. 8, 13–24 (2013). https://doi.org/10.1038/nnano.2012.240
I.H. Im, S.J. Kim, H.W. Jang, Memristive devices for new computing paradigms. Adv. Intell. Syst. 2, 2000105 (2020). https://doi.org/10.1002/aisy.202000105
S. Seo, B.S. Kang, J.J. Lee, H.J. Ryu, S. Kim et al., Artificial van der Waals hybrid synapse and its application to acoustic pattern recognition. Nat. Commun. 11, 3936 (2020). https://doi.org/10.1038/s41467-020-17849-3
Y. Choi, S. Oh, C. Qian, J.H. Park, J.H. Cho, Vertical organic synapse expandable to 3D crossbar array. Nat. Commun. 11, 4595 (2020). https://doi.org/10.1038/s41467-020-17850-w
G. Li, D. Xie, H. Zhong, Z. Zhang, X. Fu et al., Photo-induced non-volatile VO2 phase transition for neuromorphic ultraviolet sensors. Nat. Commun. 13, 1729 (2022). https://doi.org/10.1038/s41467-022-29456-5
S. Dai, Y. Zhao, Y. Wang, J. Zhang, L. Fang et al., Recent advances in transistor-based artificial synapses. Adv. Funct. Mater. 29(42), 1903700 (2019). https://doi.org/10.1002/adfm.201903700
J. Zhu, Y. Yang, R. Jia, Z. Liang, W. Zhu et al., Ion gated synaptic transistors based on 2D van der Waals crystals with tunable diffusive dynamics. Adv. Mater. 30(21), 1800195 (2018). https://doi.org/10.1002/adma.201800195
C.S. Yang, D.S. Shang, N. Liu, E.J. Fuller, S. Agrawal et al., All-solid-state synaptic transistor with ultralow conductance for neuromorphic computing. Adv. Funct. Mater. 28(42), 1804170 (2018). https://doi.org/10.1002/adfm.201804170
E.J. Fuller, F. El Gabaly, F. Léonard, S. Agarwal, S.J. Plimpton et al., Li-ion synaptic transistor for low power analog computing. Adv. Mater. 29(4), 1604310 (2017). https://doi.org/10.1002/adma.201604310
R.D. Nikam, M. Kwak, J. Lee, K.G. Rajput, W. Banerjee et al., Near ideal synaptic functionalities in Li ion synaptic transistor using Li3POxSex electrolyte with high ionic conductivity. Sci. Rep. 9, 18883 (2019). https://doi.org/10.1038/s41598-019-55310-8
R.D. Nikam, M. Kwak, J. Lee, K.G. Rajput, H. Hwang, Controlled ionic tunneling in lithium nanoionic synaptic transistor through atomically thin graphene layer for neuromorphic computing. Adv. Electron. Mater. 6(2), 1901100 (2020). https://doi.org/10.1002/aelm.201901100
P.S. Ioannou, E. Kyriakides, O. Schneegans, J. Giapintzakis, Evidence of biorealistic synaptic behavior in diffusive Li-based two-terminal resistive switching devices. Sci. Rep. 10, 8711 (2020). https://doi.org/10.1038/s41598-020-65237-0
C. Lee, J. Lee, M. Kim, J. Woo, S.M. Koo et al., Two-terminal structured synaptic device using ionic electrochemical reaction mechanism for neuromorphic system. IEEE Electron Device Lett. 40, 546–549 (2019). https://doi.org/10.1109/LED.2019.2897777
Y. Choi, C. Lee, M. Kim, Y. Song, H. Hwang et al., Structural engineering of Li-based electronic synapse for high reliability. IEEE Electron Device Lett. 40, 1992–1995 (2019). https://doi.org/10.1109/LED.2019.2950202
C.Y. Lin, J. Chen, P.H. Chen, T.C. Chang, Y. Wu et al., Adaptive synaptic memory via lithium ion modulation in RRAM devices. Small 16(42), 2003964 (2020). https://doi.org/10.1002/smll.202003964
K. Ozawa, Lithium-ion rechargeable batteries with LiCoO2 and carbon electrodes: the LiCoO2/C system. Solid State Ionics 69, 212–221 (1994). https://doi.org/10.1016/0167-2738(94)90411-1
J. Cho, Y.J. Kim, B. Park, Novel LiCoO2 cathode material with Al2O3 coating for a Li ion cell. Chem. Mater. 12, 3788–3791 (2000). https://doi.org/10.1021/cm000511k
E. Antolini, LiCoO2: formation, structure, lithium and oxygen nonstoichiometry, electrochemical behaviour and transport properties. Solid State Ionics 170, 159–171 (2004). https://doi.org/10.1016/j.ssi.2004.04.003
Y. Lyu, X. Wu, K. Wang, Z. Feng, T. Cheng et al., An overview on the advances of LiCoO2 cathodes for lithium-ion batteries. Adv. Energy Mater. 11(2), 2000982 (2021). https://doi.org/10.1002/aenm.202000982
S. Levasseur, M. Ménétrier, E. Suard, C. Delmas, Evidence for structural defects in non-stoichiometric HT-LiCoO2: electrochemical, electronic properties and 7Li NMR studies. Solid State Ionics 128, 11–24 (2000). https://doi.org/10.1016/S0167-2738(99)00335-5
M. Shibuya, T. Nishina, T. Matsue, I. Uchida, In situ conductivity measurements of LiCoO2 film during lithium insertion/extraction by using interdigitated microarray electrodes. J. Electrochem. Soc. 143, 3157–3160 (1996). https://doi.org/10.1149/1.1837180
Y. Takahashi, Y. Gotoh, J. Akimoto, S. Mizuta, K. Tokiwa et al., Anisotropic electrical conductivity in LiCoO2 single crystal. J. Solid State Chem. 164, 1–4 (2002). https://doi.org/10.1006/jssc.2001.9459
S. Yamakawa, H. Yamasaki, T. Koyama, R. Asahi, Numerical study of Li diffusion in polycrystalline LiCoO2. J. Power Sources 223, 199–205 (2013). https://doi.org/10.1016/j.jpowsour.2012.09.055
P.J. Bouwman, B.A. Boukamp, H.J.M. Bouwmeester, P.H.L. Notten, Influence of diffusion plane orientation on electrochemical properties of thin film LiCoO2 electrodes. J. Electrochem. Soc. 149, A699 (2002). https://doi.org/10.1149/1.1471543
H.S. Lee, C. Park, C.S. Oh, H.S. Lee, H.I. Seo et al., Atomic structure and defect energetics of LiCoO2 grain boundary. Mater. Res. Bull. 82, 81–86 (2016). https://doi.org/10.1016/j.materresbull.2016.04.017
H. Moriwake, A. Kuwabara, C.A.J. Fisher, R. Huang, T. Hitosugi et al., First-principles calculations of lithium-ion migration at a coherent grain boundary in a cathode material, LiCoO2. Adv. Mater. 25(4), 618–622 (2013). https://doi.org/10.1002/adma.201202805
H. Xia, L. Lu, G. Ceder, Li diffusion in LiCoO2 thin films prepared by pulsed laser deposition. J. Power Sources 159, 1422–1427 (2006). https://doi.org/10.1016/j.jpowsour.2005.12.012
P.J. Bouwman, B.A. Boukamp, H.J.M. Bouwmeester, P.H.L. Notten, Structure-related intercalation behaviour of LiCoO2 films. Solid State Ionics 152–153, 181–188 (2002). https://doi.org/10.1016/S0167-2738(02)00298-9
H. Xia, L. Lu, Texture effect on the electrochemical properties of LiCoO2 thin films prepared by PLD. Electrochim. Acta 52, 7014–7021 (2007). https://doi.org/10.1016/j.electActa2007.05.019
P. Bach, M. Stratmann, I. Valencia-Jaime, A.H. Romero, F.U. Renner, Lithiation and delithiation mechanisms of gold thin film model anodes for lithium ion batteries: electrochemical characterization. Electrochim. Acta 164, 81–89 (2015). https://doi.org/10.1016/j.electActa2015.02.184
P. Bach, I. Valencia-Jaime, U. Rütt, O. Gutowski, A.H. Romero et al., Electrochemical lithiation cycles of gold anodes observed by in situ high-energy X-ray diffraction. Chem. Mater. 28, 2941–2948 (2016). https://doi.org/10.1021/acs.chemmater.5b04719
A.D. Pelton, The Au−Li (Gold–Lithium) system. Bull. Alloy Phase Diagr. 7, 228–231 (1986). https://doi.org/10.1007/BF02868994
R.C. Atkinson, R.M. Shiffrin, Human memory: a proposed system and its control processes. Psychol. Learn. Motiv. 2, 89–195 (1968). https://doi.org/10.1016/S0079-7421(08)60422-3
D.V. Buonomano, Decoding temporal information: a model based on short-term synaptic plasticity. J. Neurosci. 20, 1129–1141 (2000). https://doi.org/10.1523/JNEUROSCI.20-03-01129.2000
P.E. Schulz, E.P. Cook, D. Johnston, Changes in paired-pulse facilitation suggest presynaptic involvement in long-term potentiation. J. Neurosci. 14, 5325–5337 (1994). https://doi.org/10.1523/JNEUROSCI.14-09-05325.1994
D.E. Feldman, Timing-based LTP and LTD at vertical inputs to layer II/III pyramidal cells in rat barrel cortex. Neuron 27, 45–56 (2000). https://doi.org/10.1016/S0896-6273(00)00008-8
G. Bi, M. Poo, Synaptic modifications in cultured hippocampal neurons: dependence on spike timing, synaptic strength, and postsynaptic cell type. J. Neurosci. 18, 10464–10472 (1998). https://doi.org/10.1523/JNEUROSCI.18-24-10464.1998
H. Markram, J. Lübke, M. Frotscher, B. Sakmann, Regulation of synaptic efficacy by coincidence of postsynaptic APs and EPSPs. Science 275(5297), 213–215 (1997). https://doi.org/10.1126/science.275.5297.213
R.S. Zucker, W.G. Regehr, Short-term synaptic plasticity. Annu. Rev. Physiol. 64, 355–405 (2002). https://doi.org/10.1146/annurev.physiol.64.092501.114547
L. Dahéron, R. Dedryvère, H. Martinez, M. Ménétrier, C. Denage et al., Electron transfer mechanisms upon lithium deintercalation from LiCoO2 to CoO2 investigated by XPS. Chem. Mater. 20, 583–590 (2008). https://doi.org/10.1021/cm702546s
J.C. Dupin, D. Gonbeau, H. Benqlilou-Moudden, P. Vinatier, A. Levasseur, XPS analysis of new lithium cobalt oxide thin-films before and after lithium deintercalation. Thin Solid Films 384, 23–32 (2001). https://doi.org/10.1016/S0040-6090(00)01802-2
C. Julien, Local cationic environment in lithium nickel–cobalt oxides used as cathode materials for lithium batteries. Solid State Ionics 136, 887–896 (2000). https://doi.org/10.1016/S0167-2738(00)00503-8
M. Inaba, Y. Iriyama, Z. Ogumi, Y. Todzuka, A. Tasaka, Raman study of layered rock-salt LiCoO2 and its electrochemical lithium deintercalation. J. Raman Spectrosc. 28, 613–617 (1997). https://doi.org/10.1002/(SICI)1097-4555(199708)28:8%3c613::AID-JRS138%3e3.0.CO;2-T
Y. LeCun, C. Cortes, The MNISTdatabase of handwritten digit images for machine learning research. (2010). http://yann.lecun.com/exdb/mnist
A. Krizhevsky, V. Nair, G. Hinton, CIFAR-10 (Canadian Institute for Advanced Research). http://www.cs.toronto.edu/~kriz/cifar.html
A. Krizhevsky, V. Nair, G. Hinton, CIFAR-100 (Canadian Institute for Advanced Research). http://www.cs.toronto.edu/~kriz/cifar.html
J. Deng, W. Dong, R. Socher, L.J. Li, K. Li et al., ImageNet: a large-scale hierarchical image database. In: 2009 IEEE Conference on Computer Vision Pattern Recognition, Miami, FL, USA, (2009). https://doi.org/10.1109/CVPR.2009.5206848
T.P. Xiao, C.H. Bennett, B. Feinberg, M.J. Marinella, S. Agarwal, CrossSim: accuracy simulation of analog in-memory computing. https://github.com/sandialabs/cross-sim
X. Xu, Y. Ding, S.X. Hu, M. Niemier, J. Cong et al., Scaling for edge inference of deep neural networks. Nat. Electron. 1, 216–222 (2018). https://doi.org/10.1038/s41928-018-0059-3
S. Ruder, An overview of gradient descent optimization algorithms. ArXiv, 1609.04747 (2016). https://doi.org/10.48550/arXiv.1609.04747