Sn-doped BiOCl nanosheet with synergistic H+/Zn2+ co-insertion for “rocking chair” zinc-ion battery

Abstract

The development of insertion-type anodes is the key to designing “rocking chair” zinc-ion batteries. However, there is rare report on high mass loading anode with high performances. Here, {001}-oriented BiOCl nanosheets with Sn doping are proposed as a promising insertion-type anode. The designs of cross-linked CNTs conductive network, {001}-oriented nanosheet, and Sn doping significantly enhance ion/electron transport, proved via experimental tests and theoretical calculations (density of states and diffusion barrier). The H+/Zn2+ synergistic co-insertion mechanism is proved via ex situ XRD, Raman, XPS, and SEM tests. Accordingly, this optimized electrode delivers a high reversible capacity of 194 mA h g−1 at 0.1 A g−1 with a voltage of ≈0.37 V and an impressive cyclability with 128 mA h g−1 over 2500 cycles at 1 A g−1. It also shows satisfactory performances at an ultrahigh mass loading of 10 mg cm−2. Moreover, the Sn-BiOCl//MnO2 full cell displays a reversible capacity of 85 mA h g−1 at 0.2 A g−1 during cyclic test.