Newly Design Porous/Sponge Red Phosphorus@Graphene and Highly Conductive Ni2P Electrode for Asymmetric Solid State Supercapacitive Device With Excellent Performance
Corresponding Author: Jeong In Han
Nano-Micro Letters,
Vol. 12 (2020), Article Number: 25
Abstract
Supercapacitors have attracted much attention in the field of electrochemical energy storage. However, material preparation, stability, performance as well as power density limit their applications in many fields. Herein, a sponge-like red phosphorus@graphene (rP@rGO) negative electrode and a Ni2P positive electrode were prepared using a simple one-step method. Both electrodes showed excellent performances (294 F g−1 and 1526.6 F g−1 for rP@rGO and Ni2P, respectively), which seem to be the highest among all rP@rGO- and Ni2P-based electrodes reported so far. The asymmetric solid-state supercapacitor was assembled by sandwiching a gel electrolyte-soaked cellulose paper between rP@rGO and Ni2P as the negative and positive electrodes. Compared to other asymmetric devices, the device, which attained a high operating window of up to 1.6 V, showed high energy and power density values of 41.66 and 1200 W kg−1, respectively. It also has an excellent cyclic stability up to 88% after various consecutive charge/discharge tests. Additionally, the device could power commercial light emitting diodes and fans for 30 s. So, the ease of the synthesis method and excellent performance of the prepared electrode materials mat have significant potential for energy storage applications.
Highlights:
1 Three-dimensional phosphorus@graphene is established as a negative electrode and Ni2P as a positive electrode for asymmetric supercapacitor.
2 The supercapacitor shows higher performance than those of all Ni2P-based electrodes, which has an extended operating voltage window of 1.6 V, energy density of 41.66 Wh Kg−1 and rate capability of up to 88% after 5000 cycles.
Keywords
Download Citation
Endnote/Zotero/Mendeley (RIS)BibTeX
- S. Liu, H. Xu, X. Bian, J. Feng, J. Liu et al., Hollow nanoporous red phosphorus as an advanced anode for sodium-ion batteries. J. Mater. Chem. A 6, 12992–12998 (2018). https://doi.org/10.1039/C8TA03301C
- Z. Chen, D.-B. Xiong, X. Zhang, H. Ma, M. Xia, Y. Zhao, Construction of a novel hierarchical structured NH4–Co–Ni phosphate toward an ultra-stable aqueous hybrid capacitor. Nanoscale 8, 6636–6645 (2016). https://doi.org/10.1039/C5NR08963H
- C. Jing, X. Liu, H.C. Yao, P. Yan et al., Phase and morphology evolution of CoAl LDH nanosheets towards advanced supercapacitor applications. CrystEngComm 21, 4934–4942 (2019). https://doi.org/10.1039/C9CE00905A
- C. Jing, X. Liu, X. Liu, D. Jiang, B. Dong et al., Crystal morphology evolution of Ni–Co layered double hydroxide nanostructure towards high-performance biotemplate asymmetric supercapacitors. CrystEngComm 20, 7428–7434 (2018). https://doi.org/10.1039/C8CE01607K
- B. Senthilkumar, K.V. Sankar, L. Vasylechko, Y.-S. Lee, R.K. Selvan, Synthesis and electrochemical performances of maricite-NaMPO4 (M = Ni, Co, Mn) electrodes for hybrid supercapacitors. RSC Adv. 4, 53192–53200 (2014). https://doi.org/10.1039/C4RA06050D
- C. Jing, Y. Zhu, X. Liu, X. Ma, F. Dong et al., Morphology and crystallinity-controlled synthesis of etched CoAlLDO/MnO2 hybrid nanoarrays towards high performance supercapacitors. J. Alloys Compd. 806, 917–925 (2019). https://doi.org/10.1016/j.jallcom.2019.07.304
- K. Zhou, W. Zhou, L. Yang, J. Lu, S. Cheng et al., Ultrahigh-performance pseudocapacitor electrodes based on transition metal phosphide nanosheets array via phosphorization: a general and effective approach. Adv. Funct. Mater. 25, 7530–7538 (2015). https://doi.org/10.1002/adfm.201503662
- S. Duan, R. Wang, Au/Ni12P5 core/shell nanocrystals from bimetallic heterostructures: in situ synthesis, evolution and supercapacitor properties. NPG Asia Mater. 6, 122 (2014). https://doi.org/10.1038/am.2014.65
- D. Wang, L.-B. Kong, M.-C. Liu, Y.-C. Luo, L. Kang, An approach to preparing Ni–P with different phases for use as supercapacitor electrode materials. Chem. Eur. J. 21, 17897–17903 (2015). https://doi.org/10.1002/chem.201502269
- D. Wang, L.-B. Kong, M.-C. Liu, W.-B. Zhang, Y.-C. Luo, L. Kang, Amorphous Ni–P materials for high performance pseudocapacitors. J. Power Sources 274, 1107–1113 (2015). https://doi.org/10.1016/j.jpowsour.2014.10.179
- I. Zafiropoulou, K. Papagelis, N. Boukos, A. Siokou, D. Niarchos, V. Tzitzios, Chemical synthesis and self-assembly of hollow Ni/Ni2P hybrid nanospheres. J. Phys. Chem. C 114, 7582–7585 (2010). https://doi.org/10.1021/jp910160g
- S. Hou, X. Xu, M. Wang, Y. Xu, T. Lu, Y. Yao, L. Pan, Carbon-incorporated Janus-type Ni2P/Ni hollow spheres for high performance hybrid supercapacitors. J. Mater. Chem. A 5, 19054–19061 (2017). https://doi.org/10.1039/C7TA04720G
- S. Xie, J. Gou, Facile synthesis of Ni2P/Ni12P5 composite as long-life electrode material for hybrid supercapacitor. J. Alloys Compd. 713, 10–17 (2017). https://doi.org/10.1016/j.jallcom.2017.04.170
- Y. Lu, J. Liu, X. Liu, S. Huang, T. Wang et al., Facile synthesis of Ni-coated Ni2P for supercapacitor applications. CrystEngComm 15, 7071 (2013). https://doi.org/10.1039/c3ce41214h
- F. Shi, D. Xie, Y. Zhong, D.H. Wang, X.H. Xia, C.D. Gu, X.L. Wang, J.P. Tu, Facile synthesis of self-supported Ni2P nanosheet@Ni sponge composite for high-rate battery. J. Power Sources 328, 405–412 (2016). https://doi.org/10.1016/j.jpowsour.2016.08.051
- Q. Zhao, Y. Han, X. Huang, J. Dai, J. Tian, Z. Zhu, L. Yue, Hydrothermal synthesis of Ni2P nanoparticle and its hydrodesulfurization of dibenzothiophene. J. Nanopart. Res. 19, 123 (2017). https://doi.org/10.1007/s11051-017-3781-2
- X. Wang, H.-M. Kim, Y. Xiao, Y.-K. Sun, Nanostructured metal phosphide-based materials for electrochemical energy storage. J. Mater. Chem. A 4, 14915–14931 (2016). https://doi.org/10.1039/C6TA06705K
- W. Du, R. Kang, P. Geng, X. Xiong, D. Li, Q. Tian, H. Pang, New asymmetric and symmetric supercapacitor cells based on nickel phosphide nanoparticles. Mater. Chem. Phys. 165, 207–214 (2015). https://doi.org/10.1016/j.matchemphys.2015.09.020
- W. Du, S. Wei, K. Zhou, J. Guo, H. Pang, X. Qian, One-step synthesis and graphene-modification to achieve nickel phosphide nanoparticles with electrochemical properties suitable for supercapacitors. Mater. Res. Bull. 61, 333–339 (2015). https://doi.org/10.1016/j.materresbull.2014.10.038
- Y. Jin, C. Zhao, L. Wang, Q. Jiang, C. Ji, X. He, Preparation of mesoporous Ni2P nanobelts with high performance for electrocatalytic hydrogen evolution and supercapacitor. Int. J. Hydrogen Energy 43, 3697–3704 (2018). https://doi.org/10.1016/j.ijhydene.2018.01.008
- H.R. Naderi, P. Norouzi, M.R. Ganjali, H. Gholipour-Ranjbar, Synthesis of a novel magnetite/nitrogen-doped reduced graphene oxide nanocomposite as high performance supercapacitor. Powder Technol. 302, 298–308 (2016). https://doi.org/10.1016/j.powtec.2016.08.054
- M. Khalid, H. Varela, A general potentiodynamic approach for red phosphorus and sulfur nanodot incorporation on reduced graphene oxide sheets: metal-free and binder-free electrodes for supercapacitor and hydrogen evolution activities. J. Mater. Chem. A 6, 3141–3150 (2018). https://doi.org/10.1039/C7TA11342K
- C. Jing, Y. Huang, L. Xia, Y. Chen, X. Wang et al., Growth of cobalt-aluminum layered double hydroxide nanosheets on graphene oxide towards high performance supercapacitors: the important role of layer structure, Author links open overlay panel. Appl. Surf. Sci. 496, 143700 (2019). https://doi.org/10.1016/j.apsusc.2019.143700
- Z.S. Wu, G. Zhou, L.C. Yin, W. Ren, F. Li, H.M. Cheng, Graphene/metal oxide composite electrode materials for energy storage. Nano Energy 1, 107–131 (2012). https://doi.org/10.1016/j.nanoen.2011.11.001
- Z. Yu, J. Song, M.L. Gordin, R. Yi, D. Tang, D. Wang, Phosphorus-graphene nanosheet hybrids as lithium-ion anode with exceptional high-temperature cycling stability. Adv. Sci. 2, 1400020 (2015). https://doi.org/10.1002/advs.201400020
- Y. Liu, N. Zhang, X. Liu, C. Chen, L.-Z. Fan, L. Jiao, Red phosphorus nanoparticles embedded in porous N-doped carbon nanofibers as high-performance anode for sodium-ion batteries. Energy Storage Mater. 9, 170–178 (2017). https://doi.org/10.1016/j.ensm.2017.07.012
- X. Zhu, Z. Yuan, X. Wang, G. Jiang, J. Xiong, S. Yuan, Hydrothermal synthesis of red phosphorus@reduced graphene oxide nanohybrid with enhanced electrochemical performance as anode material of lithium-ion battery. Appl. Surf. Sci. 433, 125–132 (2018). https://doi.org/10.1016/j.apsusc.2017.09.256
- Y. Zhu, Y. Wen, X. Fan, T. Gao, F. Han, C. Luo, S.-C. Liou, C. Wang, Red phosphorus-single-walled carbon nanotube composite as a superior anode for sodium ion batteries. ACS Nano 9, 3254–3264 (2015). https://doi.org/10.1021/acsnano.5b00376
- B. Wang, X. Huang, Z. Zhu, H. Huang, J. Dai, Hydrothermal synthesis method of nickel phosphide nanoparticles. Appl. Nanosci. 2, 423–427 (2012). https://doi.org/10.1007/s13204-012-0057-0
- K. Wang, J. Yang, J. Zhu, L. Li, Y. Liu, C. Zhang, T. Liu, General solution-processed formation of porous transition-metal oxides on exfoliated molybdenum disulfides for high-performance asymmetric supercapacitors. J. Mater. Chem. A 5, 11236–11245 (2017). https://doi.org/10.1039/C7TA01457K
- D. Wu, T. Xiao, X. Tan, P. Xiang, L. Jiang, Z. Kang, P. Tan, High-performance asymmetric supercapacitors based on cobalt chloride carbonate hydroxide nanowire arrays and activated carbon. Electrochim. Acta 198, 1–9 (2016). https://doi.org/10.1016/j.electacta.2016.01.194
- A.A. Mirghni, M.J. Madito, K.O. Oyedotun, T.M. Masikhwa, N.M. Ndiaye, S.J. Ray, N. Manyala, A high energy density asymmetric supercapacitor utilizing a nickel phosphate/graphene foam composite as the cathode and carbonized iron cations adsorbed onto polyaniline as the anode. RSC Adv. 8, 11608–11621 (2018). https://doi.org/10.1039/C7RA12028A
- S. Surendran, S. Shanmugapriya, S. Shanmugam, L. Vasylechko, R. Kalai Selvan, Interweaved nickel phosphide sponge as an electrode for flexible supercapattery and water splitting applications. ACS Appl. Energy Mater. 1, 78–92 (2018). https://doi.org/10.1021/acsaem.7b00006
- Y.M. Hu, M.-C. Liu, Y.-X. Hu, Q.-Q. Yang, L.-B. Kong, W. Han, J.-J. Li, L. Kang, Design and synthesis of Ni2P/Co3V2O8 nanocomposite with enhanced electrochemical capacitive properties. Electrochim. Acta 190, 1041–1049 (2016). https://doi.org/10.1016/j.electacta.2015.12.141
- Y. Liu, D. Luo, K. Shi, X. Michaud, I. Zhitomirsky, Asymmetric supercapacitor based on MnO2 and Fe2O3 nanotube active materials and graphene current collectors. Nano-Struct. Nano-Objects 15, 98–106 (2018). https://doi.org/10.1016/j.nanoso.2017.08.010
- B. Li, Y. Fu, H. Xia, X. Wang, High-performance asymmetric supercapacitors based on MnFe2O4/graphene nanocomposite as anode material. Mater. Lett. 122, 193–196 (2014). https://doi.org/10.1016/j.matlet.2014.02.046
- H. Gao, F. Xiao, C.B. Ching, H. Duan, High-performance asymmetric supercapacitor based on graphene hydrogel and nanostructured MnO2. ACS Appl. Mater. Interfaces 4, 2801–2810 (2012). https://doi.org/10.1021/am300455d
- P. Yang, Y. Ding, Z. Lin, Z. Chen, Y. Li et al., Low-cost high-performance solid-state asymmetric supercapacitors based on MnO2 nanowires and Fe2O3 nanotubes. Nano Lett. 14, 731–736 (2014). https://doi.org/10.1021/nl404008e
References
S. Liu, H. Xu, X. Bian, J. Feng, J. Liu et al., Hollow nanoporous red phosphorus as an advanced anode for sodium-ion batteries. J. Mater. Chem. A 6, 12992–12998 (2018). https://doi.org/10.1039/C8TA03301C
Z. Chen, D.-B. Xiong, X. Zhang, H. Ma, M. Xia, Y. Zhao, Construction of a novel hierarchical structured NH4–Co–Ni phosphate toward an ultra-stable aqueous hybrid capacitor. Nanoscale 8, 6636–6645 (2016). https://doi.org/10.1039/C5NR08963H
C. Jing, X. Liu, H.C. Yao, P. Yan et al., Phase and morphology evolution of CoAl LDH nanosheets towards advanced supercapacitor applications. CrystEngComm 21, 4934–4942 (2019). https://doi.org/10.1039/C9CE00905A
C. Jing, X. Liu, X. Liu, D. Jiang, B. Dong et al., Crystal morphology evolution of Ni–Co layered double hydroxide nanostructure towards high-performance biotemplate asymmetric supercapacitors. CrystEngComm 20, 7428–7434 (2018). https://doi.org/10.1039/C8CE01607K
B. Senthilkumar, K.V. Sankar, L. Vasylechko, Y.-S. Lee, R.K. Selvan, Synthesis and electrochemical performances of maricite-NaMPO4 (M = Ni, Co, Mn) electrodes for hybrid supercapacitors. RSC Adv. 4, 53192–53200 (2014). https://doi.org/10.1039/C4RA06050D
C. Jing, Y. Zhu, X. Liu, X. Ma, F. Dong et al., Morphology and crystallinity-controlled synthesis of etched CoAlLDO/MnO2 hybrid nanoarrays towards high performance supercapacitors. J. Alloys Compd. 806, 917–925 (2019). https://doi.org/10.1016/j.jallcom.2019.07.304
K. Zhou, W. Zhou, L. Yang, J. Lu, S. Cheng et al., Ultrahigh-performance pseudocapacitor electrodes based on transition metal phosphide nanosheets array via phosphorization: a general and effective approach. Adv. Funct. Mater. 25, 7530–7538 (2015). https://doi.org/10.1002/adfm.201503662
S. Duan, R. Wang, Au/Ni12P5 core/shell nanocrystals from bimetallic heterostructures: in situ synthesis, evolution and supercapacitor properties. NPG Asia Mater. 6, 122 (2014). https://doi.org/10.1038/am.2014.65
D. Wang, L.-B. Kong, M.-C. Liu, Y.-C. Luo, L. Kang, An approach to preparing Ni–P with different phases for use as supercapacitor electrode materials. Chem. Eur. J. 21, 17897–17903 (2015). https://doi.org/10.1002/chem.201502269
D. Wang, L.-B. Kong, M.-C. Liu, W.-B. Zhang, Y.-C. Luo, L. Kang, Amorphous Ni–P materials for high performance pseudocapacitors. J. Power Sources 274, 1107–1113 (2015). https://doi.org/10.1016/j.jpowsour.2014.10.179
I. Zafiropoulou, K. Papagelis, N. Boukos, A. Siokou, D. Niarchos, V. Tzitzios, Chemical synthesis and self-assembly of hollow Ni/Ni2P hybrid nanospheres. J. Phys. Chem. C 114, 7582–7585 (2010). https://doi.org/10.1021/jp910160g
S. Hou, X. Xu, M. Wang, Y. Xu, T. Lu, Y. Yao, L. Pan, Carbon-incorporated Janus-type Ni2P/Ni hollow spheres for high performance hybrid supercapacitors. J. Mater. Chem. A 5, 19054–19061 (2017). https://doi.org/10.1039/C7TA04720G
S. Xie, J. Gou, Facile synthesis of Ni2P/Ni12P5 composite as long-life electrode material for hybrid supercapacitor. J. Alloys Compd. 713, 10–17 (2017). https://doi.org/10.1016/j.jallcom.2017.04.170
Y. Lu, J. Liu, X. Liu, S. Huang, T. Wang et al., Facile synthesis of Ni-coated Ni2P for supercapacitor applications. CrystEngComm 15, 7071 (2013). https://doi.org/10.1039/c3ce41214h
F. Shi, D. Xie, Y. Zhong, D.H. Wang, X.H. Xia, C.D. Gu, X.L. Wang, J.P. Tu, Facile synthesis of self-supported Ni2P nanosheet@Ni sponge composite for high-rate battery. J. Power Sources 328, 405–412 (2016). https://doi.org/10.1016/j.jpowsour.2016.08.051
Q. Zhao, Y. Han, X. Huang, J. Dai, J. Tian, Z. Zhu, L. Yue, Hydrothermal synthesis of Ni2P nanoparticle and its hydrodesulfurization of dibenzothiophene. J. Nanopart. Res. 19, 123 (2017). https://doi.org/10.1007/s11051-017-3781-2
X. Wang, H.-M. Kim, Y. Xiao, Y.-K. Sun, Nanostructured metal phosphide-based materials for electrochemical energy storage. J. Mater. Chem. A 4, 14915–14931 (2016). https://doi.org/10.1039/C6TA06705K
W. Du, R. Kang, P. Geng, X. Xiong, D. Li, Q. Tian, H. Pang, New asymmetric and symmetric supercapacitor cells based on nickel phosphide nanoparticles. Mater. Chem. Phys. 165, 207–214 (2015). https://doi.org/10.1016/j.matchemphys.2015.09.020
W. Du, S. Wei, K. Zhou, J. Guo, H. Pang, X. Qian, One-step synthesis and graphene-modification to achieve nickel phosphide nanoparticles with electrochemical properties suitable for supercapacitors. Mater. Res. Bull. 61, 333–339 (2015). https://doi.org/10.1016/j.materresbull.2014.10.038
Y. Jin, C. Zhao, L. Wang, Q. Jiang, C. Ji, X. He, Preparation of mesoporous Ni2P nanobelts with high performance for electrocatalytic hydrogen evolution and supercapacitor. Int. J. Hydrogen Energy 43, 3697–3704 (2018). https://doi.org/10.1016/j.ijhydene.2018.01.008
H.R. Naderi, P. Norouzi, M.R. Ganjali, H. Gholipour-Ranjbar, Synthesis of a novel magnetite/nitrogen-doped reduced graphene oxide nanocomposite as high performance supercapacitor. Powder Technol. 302, 298–308 (2016). https://doi.org/10.1016/j.powtec.2016.08.054
M. Khalid, H. Varela, A general potentiodynamic approach for red phosphorus and sulfur nanodot incorporation on reduced graphene oxide sheets: metal-free and binder-free electrodes for supercapacitor and hydrogen evolution activities. J. Mater. Chem. A 6, 3141–3150 (2018). https://doi.org/10.1039/C7TA11342K
C. Jing, Y. Huang, L. Xia, Y. Chen, X. Wang et al., Growth of cobalt-aluminum layered double hydroxide nanosheets on graphene oxide towards high performance supercapacitors: the important role of layer structure, Author links open overlay panel. Appl. Surf. Sci. 496, 143700 (2019). https://doi.org/10.1016/j.apsusc.2019.143700
Z.S. Wu, G. Zhou, L.C. Yin, W. Ren, F. Li, H.M. Cheng, Graphene/metal oxide composite electrode materials for energy storage. Nano Energy 1, 107–131 (2012). https://doi.org/10.1016/j.nanoen.2011.11.001
Z. Yu, J. Song, M.L. Gordin, R. Yi, D. Tang, D. Wang, Phosphorus-graphene nanosheet hybrids as lithium-ion anode with exceptional high-temperature cycling stability. Adv. Sci. 2, 1400020 (2015). https://doi.org/10.1002/advs.201400020
Y. Liu, N. Zhang, X. Liu, C. Chen, L.-Z. Fan, L. Jiao, Red phosphorus nanoparticles embedded in porous N-doped carbon nanofibers as high-performance anode for sodium-ion batteries. Energy Storage Mater. 9, 170–178 (2017). https://doi.org/10.1016/j.ensm.2017.07.012
X. Zhu, Z. Yuan, X. Wang, G. Jiang, J. Xiong, S. Yuan, Hydrothermal synthesis of red phosphorus@reduced graphene oxide nanohybrid with enhanced electrochemical performance as anode material of lithium-ion battery. Appl. Surf. Sci. 433, 125–132 (2018). https://doi.org/10.1016/j.apsusc.2017.09.256
Y. Zhu, Y. Wen, X. Fan, T. Gao, F. Han, C. Luo, S.-C. Liou, C. Wang, Red phosphorus-single-walled carbon nanotube composite as a superior anode for sodium ion batteries. ACS Nano 9, 3254–3264 (2015). https://doi.org/10.1021/acsnano.5b00376
B. Wang, X. Huang, Z. Zhu, H. Huang, J. Dai, Hydrothermal synthesis method of nickel phosphide nanoparticles. Appl. Nanosci. 2, 423–427 (2012). https://doi.org/10.1007/s13204-012-0057-0
K. Wang, J. Yang, J. Zhu, L. Li, Y. Liu, C. Zhang, T. Liu, General solution-processed formation of porous transition-metal oxides on exfoliated molybdenum disulfides for high-performance asymmetric supercapacitors. J. Mater. Chem. A 5, 11236–11245 (2017). https://doi.org/10.1039/C7TA01457K
D. Wu, T. Xiao, X. Tan, P. Xiang, L. Jiang, Z. Kang, P. Tan, High-performance asymmetric supercapacitors based on cobalt chloride carbonate hydroxide nanowire arrays and activated carbon. Electrochim. Acta 198, 1–9 (2016). https://doi.org/10.1016/j.electacta.2016.01.194
A.A. Mirghni, M.J. Madito, K.O. Oyedotun, T.M. Masikhwa, N.M. Ndiaye, S.J. Ray, N. Manyala, A high energy density asymmetric supercapacitor utilizing a nickel phosphate/graphene foam composite as the cathode and carbonized iron cations adsorbed onto polyaniline as the anode. RSC Adv. 8, 11608–11621 (2018). https://doi.org/10.1039/C7RA12028A
S. Surendran, S. Shanmugapriya, S. Shanmugam, L. Vasylechko, R. Kalai Selvan, Interweaved nickel phosphide sponge as an electrode for flexible supercapattery and water splitting applications. ACS Appl. Energy Mater. 1, 78–92 (2018). https://doi.org/10.1021/acsaem.7b00006
Y.M. Hu, M.-C. Liu, Y.-X. Hu, Q.-Q. Yang, L.-B. Kong, W. Han, J.-J. Li, L. Kang, Design and synthesis of Ni2P/Co3V2O8 nanocomposite with enhanced electrochemical capacitive properties. Electrochim. Acta 190, 1041–1049 (2016). https://doi.org/10.1016/j.electacta.2015.12.141
Y. Liu, D. Luo, K. Shi, X. Michaud, I. Zhitomirsky, Asymmetric supercapacitor based on MnO2 and Fe2O3 nanotube active materials and graphene current collectors. Nano-Struct. Nano-Objects 15, 98–106 (2018). https://doi.org/10.1016/j.nanoso.2017.08.010
B. Li, Y. Fu, H. Xia, X. Wang, High-performance asymmetric supercapacitors based on MnFe2O4/graphene nanocomposite as anode material. Mater. Lett. 122, 193–196 (2014). https://doi.org/10.1016/j.matlet.2014.02.046
H. Gao, F. Xiao, C.B. Ching, H. Duan, High-performance asymmetric supercapacitor based on graphene hydrogel and nanostructured MnO2. ACS Appl. Mater. Interfaces 4, 2801–2810 (2012). https://doi.org/10.1021/am300455d
P. Yang, Y. Ding, Z. Lin, Z. Chen, Y. Li et al., Low-cost high-performance solid-state asymmetric supercapacitors based on MnO2 nanowires and Fe2O3 nanotubes. Nano Lett. 14, 731–736 (2014). https://doi.org/10.1021/nl404008e