1D Insertion Chains Induced Small‐Polaron Collapse in MoS<sub>2</sub> 2D Layers Toward Fast‐Charging Sodium‐Ion Batteries
Zhuoran Lv, Chendong Zhao, Miao Xie, Mingzhi Cai, Baixin Peng, Dayong Ren, Yuqiang Fang, Wujie Dong, Wei Zhao, Tianquan Lin, Ximeng Lv, Gengfeng Zheng, Fuqiang Huang
Abstract
Abstract Molybdenum disulfide (MoS 2 ) with high theoretical capacity is viewed as a promising anode for sodium‐ion batteries but suffers from inferior rate capability owing to the polaron‐induced slow charge transfer. Herein, a polaron collapse strategy induced by electron‐rich insertions is proposed to effectively solve the above issue. Specifically, 1D [MoS] chains are inserted into MoS 2 to break the symmetry states of 2D layers and induce small‐polaron collapse to gain fast charge transfer so that the as‐obtained thermodynamically stable Mo 2 S 3 shows metallic behavior with 10 7 times larger electrical conductivity than that of MoS 2 . Theoretical calculations demonstrate that Mo 2 S 3 owns highly delocalized anions, which substantially reduce the interactions of Na−S to efficiently accelerate Na + diffusion, endowing Mo 2 S 3 lower energy barrier (0.38 vs 0.65 eV of MoS 2 ). The novel Mo 2 S 3 anode exhibits a high capacity of 510 mAh g −1 at 0.5 C and a superior high‐rate stability of 217 mAh g −1 at 40 C over 15 000 cycles. Further in situ and ex situ characterizations reveal the in‐depth reversible redox chemistry in Mo 2 S 3 . The proposed polaron collapse strategy for intrinsically facilitating charge transfer can be conducive to electrode design for fast‐charging batteries.