Three-dimensional micro-nanostructures based on binary transitional metal sulfides with doped carbon protector enabled high-performance and safe batteries

The lack of suitable Li + reservoirs and the risk of thermal runaway have hindered the extended use of lithium-ion batteries. Although utilizing Li 4 Ti 5 O 12 or TiO 2 can improve the thermal safety, their low theoretical capacities compromise the electrochemical performance of the cell. In this study, a three-dimensional micro-nanostructure based on binary transitional metal sulfides (TMSs) with a doped carbon protector (SnS/Co 9 S 8 @HC) is designed. When operating at 0.1–1 A g −1, the SnS/Co 9 S 8 @HC cell exhibits a high inceptive capacity of 1104.8 mAh g −1 with a high coulomb efficiency of 97.1%. Even after 1000 cycles, it delivers a relatively-high capacity of 450.3 mAh g −1, indicating a low capacity decay rate of 0.033% per cycle (from the 2nd to the 1000th cycle). The thermal runaway actions of the cells with graphite and SnS/Co 9 S 8 @HC anodes are investigated. The results demonstrate that the cell with the SnS/Co 9 S 8 @HC anode exhibits a significantly reduced maximum thermal runaway temperature of 473.5 ± 6.2℃ and maximum temperature increasing rate of 15.1 ± 0.6 °C min −1 compared to the graphite cell. This indicates that SnS/Co 9 S 8 @HC cell holds higher thermal safety. The potential of SnS/Co 9 S 8 @HC as sodium ion batteries anode is also investigated. The results indicate an initial capacity of 631.7 mAh g −1, with a low capacity decay rate of 0.063% per cycle when operating at 2 A g −1. This work may be enlightening for constructing multi-phase TMSs based hierarchical structure towards superior and safe energy storage.