Few‐Layered Tin Sulfide Nanosheets Supported on Reduced Graphene Oxide as a High‐Performance Anode for Potassium‐Ion Batteries
2019; Wiley; Volume: 15; Issue: 10 Linguagem: Inglês
10.1002/smll.201804806
ISSN1613-6829
AutoresLingzhe Fang, Jing Xu, Shuo Sun, Baowei Lin, Qiubo Guo, Da Luo, Hui Xia,
Tópico(s)Supercapacitor Materials and Fabrication
ResumoAnodes involving conversion and alloying reaction mechanisms are attractive for potassium-ion batteries (PIBs) due to their high theoretical capacities. However, serious volume change and metal aggregation upon potassiation/depotassiation usually cause poor electrochemical performance. Herein, few-layered SnS2 nanosheets supported on reduced graphene oxide (SnS2 @rGO) are fabricated and investigated as anode material for PIBs, showing high specific capacity (448 mAh g-1 at 0.05 A g-1 ), high rate capability (247 mAh g-1 at 1 A g-1 ), and improved cycle performance (73% capacity retention after 300 cycles). In this composite electrode, SnS2 nanosheets undergo sequential conversion (SnS2 to Sn) and alloying (Sn to K4 Sn23 , KSn) reactions during potassiation/depotassiation, giving rise to a high specific capacity. Meanwhile, the hybrid ultrathin nanosheets enable fast K storage kinetics and excellent structure integrity because of fast electron/ionic transportation, surface capacitive-dominated charge storage mechanism, and effective accommodation for volume variation. This work demonstrates that K storage performance of alloy and conversion-based anodes can be remarkably promoted by subtle structure engineering.
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