Synergistically Tuning Graphene Layer and Active Sites for Flexible Zn–Air Batteries

• Published in: Advanced functional materials 2024-07
• Main Authors: Yu, Mengmeng, Guo, Feifei, Xu, Li, Zhang, Yan, Ni, Wenhui, Wang, Jun, Wei, Yichen, Chen, Xifan, Yang, Jia, Li, Hongbao, Wang, Junying, Wang, Junzhong
• Format: Article
• Language: English
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202411935

Fewer layer graphene principally has a higher surface area to support more catalytic sites for energy conversion, but it is still challenging to synthesize monolayer graphene without oxidation from graphite at a low cost. Here, a method for synergistically thinning graphene layers and constructing catalytic sites to create a superior bifunctional oxygen catalyst through vapor intercalation of multi‐layer graphene or its derivatives is described. The synthesized small sheet sizes of 1–2 layer graphene‐supported FeN 4 and FeCo active sites exhibit superior reversible activity of oxygen reduction and evolution reactions with a low overall overpotential of 0.648 V. The sheet‐shaped catalyst is further used to fabricate flexible soft‐packed and wearable cable‐type quasi‐solid‐state zinc–air batteries, achieving high performances (>188 mW cm −2 , >450 cycles) and enabling smartphone charging. DFT calculations reveal that fewer layer graphene coupled with atomic FeN 4 and alloy FeCo sites enables lower Gibbs free energy for favorable OOH* intermediate adsorption/desorption benefiting superior oxygen redox process. This study introduces a strategy for scalable synthesis of 1–2 layer graphene from cheap microcrystalline graphite minerals for wearable and durable energy devices.