Laser-Induced Ultrafine Cu-Anchored 3D CNT-rGO Carrier for Flexible and Durable Zinc-Iodine Micro-Batteries

Abstract

Three-dimensional (3D) carbon materials are often used as carriers for anchoring iodine in zinc-iodine batteries (ZIBs). However, the physical stacking of carbon materials during the electrode assembly process, the weaker physical interactions between non-polar carbon materials and iodine species, and the scarcity of catalytic sites for iodine conversion led to a reduced catalytic activity for the iodine redox reaction, which fails to completely inhibit the shuttling of iodine species. Here, 3D ultrafine Cu-anchored CNT-rGO carriers (3D Cu@CNT-rGO) with interconnected structures are prepared using a simple laser-induced reduction strategy. The 3D microporous structure and excellent electrical conductivity of 3D Cu@CNT-rGO make it an ideal host for iodine. Ultrafine Cu nanoparticles introduce as catalysts accelerate the redox kinetics, efficiently catalyze iodine/polyiodide conversion, inhibit polyiodide shuttling, and enhance the electrochemical performance of ZIBs. The fabricated zinc-iodide micro-batteries (ZIMBs) delivers a high specific area capacity of 1.29 mAh cm⁻², a high area energy density (1.55 mWh cm⁻²) and a high area power density (33.58 mW cm⁻²) as well as excellent cyclin stability (80% capacity retention after 4000 cycles). Meanwhile, ZIMBs have excellent mechanical flexibility and have great potential for application in the field of integrated, miniaturized and flexible electronic devices.