N/O-doped porous carbon matrix for improved potassium-selenium battery cathode in different electrolyte systems
JOURNAL OF ALLOYS AND COMPOUNDS(2023)
摘要
Combining the high abundance of potassium (K) in the Earth's crust and the high theoretical energy density of selenium (Se), a potassium-selenium (K-Se) battery is attractive as an alternative energy storage system. However, some urgent issues still need to be solved to obtain efficient selenium-based cathodes, such as the shuttle effect of high-order selenides in electrolytes and volume expansion during the redox process. Herein, we report Se/heteroatoms (N and O) dual-doped hierarchical porous carbon (Se/HHPC) composite as cathode material for the K-Se battery. The hierarchical porous carbon frameworks not only provide storage and ex-pansion buffer space for Se-based cathode material, but also facilitate the penetration of the electrolyte, which effectively improves the cell's electrical conductivity. In addition, the dual-doped heteroatoms enhance the interaction between potassium selenide and carbon host. When tested for K-ion batteries with carbonate electrolytes, Se/HHPC cathode exhibits a relatively high electrochemical performance (228 mAh g-1, 200 cycles, 0.2 C) under the synergy of space bondage and chemisorption. The electrode could deliver a rate capability of 295 mAh g-1 at 4 C. Furthermore, the hybrid cathode also exhibits excellent properties in ether electrolytes and has a reversible capacity of 236 mA h g-1 at 0.2 C after 300 cycles and a rate capability of 234 mAh g-1 at 4 C.(c) 2022 Elsevier B.V. All rights reserved.
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关键词
Potassium -selenium batteries, Hierarchical porous frameworks, Heteroatoms dual -doped carbon
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