Surface protection and nucleation enhancement of zinc anode with graphene and doped carbon nanotubes for high-performance energy storage

Owing to their high-power density, long cycling performance, excellent safety, and eco-friendliness, Zn-ion hybrid supercapacitors (ZIHC) have attracted attention as a next-generation energy storage technology to replace conventional lithium-ion batteries. However, the dissolution of Zn in ZIHCs, their low wettability and limited number of nucleation sites for Zn plating have limited their further application. To address these, research has been undertaken to enhance safety by applying a protective layer, such as carbon, ceramics, or polymers, onto the zinc anodes. Nevertheless, achieving exceptional energy storage performance remains insufficient. In this study sequentially coated Zn electrode surface with graphene and carbon nanotubes (CNT), and F and N were simultaneously doped in the carbon lattice of the top layer of the CNTs. Owing to its excellent safety, improved wettability, and numerous nucleation sites for Zn plating, the surface-engineered Zn anode exhibited improved energy-power density (255 to 141 Wh kg-1 between 800 and 32,000 W kg-1) and long lifespan capability of 93 % after 45,000 cycles. The proposed strategy is a highly promising approach for enhancing the energy storage performance of ZIHCs.