Few‐Atomic‐Layered Co‐Doped BiOBr Nanosheet: Free‐Standing Anode with Ultrahigh Mass Loading for “Rocking Chair” Zinc‐Ion Battery
Bei Long, Qing Zhang, Qing Zhang, Tengfei Duan, Ting Song, Yong Pei, Xianyou Wang, Chunyi Zhi, Xiongwei Wu, Qianyu Zhang, Qianyu Zhang, Yuping Wu
Abstract
Abstract Insertion host materials are considered as a candidate to replace metallic Zn anode. However, the high mass loading anode with good electrochemical performances is reported rarely. Herein, a few‐atomic‐layered Co‐doped BiOBr nanosheet (Co‐UTBiOBr) is prepared via one‐step hydrothermal method and a free‐standing flexible electrode consisting of Co‐UTBiOBr and CNTs is designed. Ultrathin nanosheet (3 atomic layers) and CNTs accelerate Zn 2+ and electron transfer respectively. The Co‐doping is conducive to the reduced Zn 2+ diffusion barrier, the improved volume expansion after Zn 2+ intercalation, and the enhanced electronic conductivity of BiOBr, verified by experimental and theoretical studies. An insertion‐conversion mechanism is proposed according to ex situ characterizations. Benefiting from many advantages, Co‐UTBiOBr displays a high capacity of 150 mAh g −1 at 0.1 A g −1 and a long‐term cyclic life with ≈100% capacity attention over 3000 cycles at 1 A g −1 . Remarkably, excellent electrochemical performances are maintained even at an ultrahigh mass loading of 15 mg cm −2 . Co‐UTBiOBr//MnO 2 “rocking chair” zinc‐ion battery exhibits a stable capacity of ≈130 mAh g −1 at 0.2 A g −1 during cyclic test and its flexible quasi‐solid‐state battery shows outstanding stability under various bending states. This work provides a new idea for designing high mass loading anode.