材料科学
插层(化学)
阳极
钾
纳米技术
金属
离子
钾离子电池
电极
过渡金属
化学工程
无机化学
冶金
催化作用
物理化学
有机化学
工程类
化学
磷酸钒锂电池
作者
Junhu Zhou,Yiheng Shen,Fan Lv,Weiyu Zhang,Fangxu Lin,Wenshu Zhang,Kai Wang,Heng Luo,Qian Wang,Huai Yang,Shaojun Guo
标识
DOI:10.1002/adfm.202204495
摘要
Abstract Transition metal dichalcogenides (TMDs) show great potential as anodes for potassium‐ion batteries (PIBs) due to their high theoretical capacity and relatively low working potential. However, usually the conversion mechanism seriously hinders the long‐term cycle stability for PIBs due to the huge structural change. Herein, the synthesis of a class of ultrathin metallic 2H‐phase NbS 2 nanosheets with large expanded interlayer spacing of 0.65 nm and high conductivity for boosting the potassium ion storage is reported. It is demonstrated that the as‐prepared NbS 2 nanosheets show an unexpected intercalation mechanism for potassium ion storage, which is conceptually different from the well‐known intercalation‐conversion mechanism of typical TMDs. As a consequence, the ultrathin NbS 2 nanosheets deliver superior rate capability (205.5 mAh g −1 at ultrahigh current density of 10 A g −1 ) and outstanding long‐term cycling performance (169.5 mAh g −1 at 5 A g −1 after 4000 cycles with a very low decay rate of 0.005% per cycle), representing the most stable TMD‐based anode materials for PIBs. Ex situ measurements and first‐principles calculations disclose and interpret that NbS 2 nanosheets store potassium ions through only the intercalation mechanism without any conversion reaction taking place in the potassiation/depotassiation process, which highly improves the structural stability of electrode materials, hence promoting the long‐term cycle performance.
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