Sun Qing, Yang Maoxiang, Zeng Guifang, Li Jing, Hu Zhibiao, Li Deping, Wang Shang, Si Pengchao, Tian Yanhong, Ci Lijie
Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Research Center for Carbon Nanomaterials, School of Materials Science and Engineering, Shandong University, Jinan, 250061, China.
State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, 150001, China.
Small. 2022 Sep;18(39):e2203459. doi: 10.1002/smll.202203459. Epub 2022 Aug 26.
Tin chalcogenides are regarded as promising anode materials for potassium ion batteries (PIBs) due to their considerable specific capacity. However, the severe volume effect, limited electronic conductivity, and the shuttle effect of the potassiation product restrict the application prospect. Herein, based on the metal evaporation reaction, a facile structural engineering strategy for yolk-shell SnSe encapsulated in carbon shell (SnSe@C) is proposed. The internal void can accommodate the volume change of the SnSe core and the carbon shell can enhance the electronic conductivity. Combining qualitative and quantitative electrochemical analyses, the distinguished electrochemical performance of SnSe@C anode is attributed to the contribution of enhanced capacitive behavior. Additionally, first-principles calculations elucidate that the heteroatomic doped carbon exhibits a preferable affinity toward potassium ions and the potassiation product K Se, boosting the rate performance and capacity retention consequently. Furthermore, the phase evolution of SnSe@C electrode during the potassiation/depotassiation process is clarified by in situ X-ray diffraction characterization, and the crystal transition from the SnSe Pnma(62) to Cmcm(63) point group is discovered unpredictably. This work demonstrates a pragmatic avenue to tailor the SnSe@C anode via a facile structural engineering strategy and chemical regulation, providing substantial clarification for the phase evolution mechanism of SnSe-based anode for PIBs.
锡硫属化合物因其可观的比容量而被视为钾离子电池（PIB）有前景的负极材料。然而，严重的体积效应、有限的电子导电性以及钾化产物的穿梭效应限制了其应用前景。在此，基于金属蒸发反应，提出了一种简便的结构工程策略，用于制备碳壳包裹的蛋黄壳型SnSe（SnSe@C）。内部空隙可容纳SnSe核的体积变化，而碳壳可提高电子导电性。结合定性和定量电化学分析，SnSe@C负极卓越的电化学性能归因于增强的电容行为的贡献。此外，第一性原理计算表明，杂原子掺杂的碳对钾离子和钾化产物K Se表现出较好的亲和力，从而提高了倍率性能和容量保持率。此外，通过原位X射线衍射表征阐明了SnSe@C电极在钾化/脱钾过程中的相演变，并意外地发现了从SnSe Pnma(62)到Cmcm(63)点群的晶体转变。这项工作展示了一条通过简便的结构工程策略和化学调控来定制SnSe@C负极的实用途径，为PIB的SnSe基负极的相演变机制提供了实质性的阐释。
