Unraveling the “Gap‐Filling” Mechanism of Multiple Charge Carriers in Aqueous Zn‐MoS<sub>2</sub> Batteries
Shengwei Li, Xudong Zhao, Tianhao Wang, Jiae Wu, Xinghe Xu, Ping Li, Xiaobo Ji, Hongshuai Hou, Xuanhui Qu, Lifang Jiao, Yongchang Liu
Abstract
Abstract The utilization rate of active sites in cathode materials for Zn‐based batteries is a key factor determining the reversible capacities. However, a long‐neglected issue of the strong electrostatic repulsions among divalent Zn 2+ in hosts inevitably causes the squander of some active sites (i.e., gap sites). Herein, we address this conundrum by unraveling the “gap‐filling” mechanism of multiple charge carriers in aqueous Zn‐MoS 2 batteries. The tailored MoS 2 /(reduced graphene quantum dots) hybrid features an ultra‐large interlayer spacing (2.34 nm), superior electrical conductivity/hydrophilicity, and robust layered structure, demonstrating highly reversible NH 4 + /Zn 2+ /H + co‐insertion/extraction chemistry in the 1 M ZnSO 4 +0.5 M (NH 4 ) 2 SO 4 aqueous electrolyte. The NH 4 + and H + ions can act as gap fillers to fully utilize the active sites and screen electrostatic interactions to accelerate the Zn 2+ diffusion. Thus, unprecedentedly high rate capability (439.5 and 104.3 mAh g −1 at 0.1 and 30 A g −1 , respectively) and ultra‐long cycling life (8000 cycles) are achieved.