Synergistic engineering of structural and electronic regulation of In2Se3 for ultrastable Li − ion battery

Abstract

As a representative two-dimensional layered material, In2Se3 attracts an increasing research interest because of the virtue of high theoretical lithium-ion storage capacity. However, the development of In2Se3-based anode is primarily confined by the poor electronic conductivity and inevitable volume variations. Moreover, the lithium − ion storage mechanism of In2Se3- based electrode is still not clear. Here, we report a facile construction strategy for metal-organic frameworks (MOFs)-derived In2Se3 nanocrystals encapsulated in porous nitrogen − doped carbon conductive matrix (In2Se3/PNC). The In2Se3/PNC with porous structure and rich N − doped carbon affords highly efficient channels for rapid transportation of ions and electrons. Meanwhile, as the heterogeneous structure provides sufficient void space to relieve the internal mechanical stress during the repeated charge–discharge processes. Thus, the optimized In2Se3/PNC − 800 (annealed at 800 °C) electrode exhibits a capacity as high as 1038 mAh/g at 200 mA g−1, remarkable cycling stability over 2000 cycles and a comparable high-rate capability. Moreover, the reaction mechanism of the In2Se3 with Li+ is revealed through in-situ XRD and density functional theory (DFT) simulations. This study may present broad opportunities for reliable construction of high-capacity selenium-based composites for energy storage.