Regulating Dendrite-Free Zinc Deposition by 3D Zincopilic Nitrogen-Doped Vertical Graphene for High-Performance Flexible Zn-Ion Batteries

The rapidly growing demand for wearable and portable electronics has driven the recent revival of flexible Zn-ion batteries (ZIBs). However, issues of dendrite growth and low the flexibility of Zn metal anode still impede their practical application. Herein, 3D nitrogen-doped vertical graphene nanosheets in situ grown on carbon cloth (N-VG@CC) are proposed to enable uniform Zn nucleation, thereby obtaining a dendrite-free and robust Zn anode. The introduced zincopilic N-containing groups in N-VG effectively reduce the Zn nucleation overpotential by enhancing the interaction between Zn2+ ion and carbon substrate, as confirmed by density functional theory calculations, thus achieving uniform distribution of Zn nucleus. Moreover, the 3D nanosheet arrays can homogenize electric distribution, which optimizes the subsequence Zn deposition process and realizes the highly reversible Zn plating/stripping process. Consequently, the as-prepared Zn@N-VG@CC anode exhibits an improved overall electrochemical performance compared with Zn@CC. As a proof-of-concept application, the high-performance Zn@N-VG@CC electrodes are successfully employed as anodes for coin and flexible quasi-solid-state ZIBs together with MnO2@N-VG@CC (deposited MnO2 nanosheets on N-VG@CC) as cathodes. More importantly, the flexible ZIB exhibits impressive cycling stability with 80% capacity retention after 300 cycles and outstanding mechanical flexibility, indicating a promising potential for portable and wearable electronics.

Automated summary

The proposed 3D nitrogen-doped vertical graphene nanosheets grown on carbon cloth improve the performance of zinc-ion batteries by achieving uniform zinc nucleation, optimizing electric distribution, and enhancing the zinc deposition/stripping process, leading to higher electrochemical performance. This technology not only achieves high cycling stability of the battery, but also exhibits outstanding mechanical flexibility, showing great potential for portable and wearable electronics.