Pre-Protonated Vanadium Hexacyanoferrate for High Energy-Power and Anti-Freezing Proton Batteries |
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Authors: | Xiaoyu Dong Zhiwei Li Derong Luo Kangsheng Huang Hui Dou Xiaogang Zhang |
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Institution: | Jiangsu Key Laboratory of Electrochemical Energy Storage Technology, College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016 P. R. China |
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Abstract: | Proton batteries have been considered as an innovative energy storage technology owing to their high safety and cost-effectiveness. However, the development of fast-charging proton batteries with high energy/power density is greatly limited by feasible material selection. Here, the pre-protonated vanadium hexacyanoferrate (H-VHCF) is developed as a proton cathode material to alleviate the capacity loss of proton-free electrode materials during electrochemical tests. The pre-protonation process realizes fast and long-distance transport of protons by shortening diffusion path and reducing migration barriers. Benefitting from the enhanced hydrogen bonding network combined with dual redox reactions of V and Fe in protonated H-VHCF cathode, a high energy density of 74 Wh kg?1 at 1.1 kW kg?1, and a maximum power density of 54 kW kg?1 at 65 Wh kg?1 is achieved for the asymmetric proton batteries coupling with MoO3/MXene anode. Proton transport and double oxidation-reduction center are verified by theoretical calculations and ex situ experimental measurements. Considering the anti-freezing availability of proton batteries, 82.5% of its initial capacity is maintained after 10000 cycles under ?40 °C at 0.5 A g?1. As a proof-of-concept, flexible device fabricated by optimized electrodes and hydrogel electrolytes can power up a light-emitting diode even under a bent state. |
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Keywords: | Gtotthuss mechanism pre-protonation proton batteries Prussian blue analogs |
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