Abstract
Sodium ion batteries (SIBs) have been considered as promising candidates for nextgeneration energy storage devices due to low costs and abundant sodium resources.However, the absence of high-performance anode materials is a big challenge for further application of SIBs. Herein, a series of cubic spinel MIn2S4 (M=Fe, Co, Mn) materials are synthesized through a two-step hydrothermal method. As a result, the FeIn2S4 exhibits a high specific capacity (618.2 mAh g-1 at 500 mA g-1), excellent rate performance (333.6 mAh g-1 at 100 A g-1), and superior long cycling stability (~277 mAh g-1 at 100 A g-1 over 20000 cycles with capacity retention of 100%). Investigated by the refined and in-situ XRD, the superior electrochemical performance of the proposed anode materials is attributed to the large unit cell volume and the complementary reaction mechanism. In addition, kinetic analyses such as pseudocapacitive contribution and in/ex-situ EIS were applied to explain the similarities and differences of electrochemical performance among the MIn2S4 (M=Fe, Co, Mn) materials. This work reveals a new strategy to enhance the anode performance with the synergetic cooperation of structure regulation and complementary reaction mechanism.