材料科学
阳极
石墨烯
化学工程
氧化物
阴极
纳米技术
电化学
电极
物理化学
化学
工程类
冶金
作者
Huanyu Liang,Yongcheng Zhang,Shujin Hao,L Cao,Yanhong Li,Qiang Li,Chen Dong,Xia Wang,Xiangxin Guo,Hongsen Li
标识
DOI:10.1016/j.ensm.2021.05.013
摘要
The increasing demand to develop sustainable energy storage equipment has aroused interest for potassium-ion capacitors (PICs), owing to their high abundance and low cost of potassium sources. Nevertheless, the practical application of PICs is impeded by the lack of suitable anode materials with high performance. Here we demonstrate a solvothermal-assisted synthesis of porous CoV2O6 [email protected] oxide (GO) composites as the anode material of PICs for the first time. Benefiting from the well-designed porous nanostructure and high-conductivity carbon incorporation, the hybrid composite delivers an initial high discharge capacity (264 mAh g−1, 1 A g−1) and superior rate capability (97 mAh g−1, 10 A g−1). Moreover, the electrochemical reaction mechanism of CoV2O6 involving an intercalation followed by conversion reaction is comprehensively revealed by first-principles calculations (DFT), ex-situ X-ray photoelectron spectroscopy as well as ex-situ high-resolution transmission electron microscopy. Meanwhile, the DFT also indicates that CoV2O6 possesses high electron/K-ion conductivity and low diffusion barriers for K+ intercalation. Consequently, PICs coupling the CoV2O6@GO anode and activated carbon cathode display a high energy/power density (78.2 Wh kg−1 and 22,500 W kg−1) as well as an ultralong lifespan over 3000 cycles. The work delves metal vanadate as high-performance anode for PICs and may provide innovative insight into electrode structure building in rechargeable metal-ions chemistry.
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