BiOI Nanopaper As a High-Capacity, Long-Life and Insertion-Type Anode for a Flexible Quasi-Solid-State Zn-Ion Battery
Qing Zhang, Tengfei Duan, Manjun Xiao, Yong Pei, Xianyou Wang, Chunyi Zhi, Xiongwei Wu, Bei Long, Yuping Wu
Abstract
The development of intercalation anodes with high capacity is key to promote the progress of “rocking-chair” Zn-ion batteries (ZIBs). Here, layered BiOI is considered as a promising electrode in ZIBs due to its large interlayer distance (0.976 nm) and low Zn2+ diffusion barrier (0.57 eV) obtained by density functional theory, and a free-standing BiOI nanopaper is designed. The process and mechanism of Zn(H2O)n2+ insertion in BiOI are proved by ex situ X-ray diffraction, Raman, and X-ray photoelectron spectroscopy. The suitable potential (0.6 V vs Zn/Zn2+), high reversible capacity (253 mAh g–1), good rate performance (171 mAh g–1 at 10 A g–1), long cyclic life (113 mAh g–1 after 5000 cycles at 5 A g–1), and dendrite-free operation of BiOI nanopaper prove its potential as a superior anode. When it is coupled with Mn3O4 cathode, the quasi-solid-state battery exhibits a high initial capacity of 149 mAh g–1 (for anode) and a good capacity retention of 70 mAh g–1 after 400 cycles. The self-assembled flexible battery also shows stable charge–discharge during the cyclic test. This work shows the feasibility of BiOX anode for dendrite-free ZIBs.