Diffusion–reaction competition governs zinc electrodeposition in three-dimensional carbon scaffolds

Abstract

Aqueous zinc-ion batteries are promising for grid-scale and stationary energy storage, yet their practical deployment requires Zn anodes capable of highly efficient electrodeposition/stripping. In this work, we show that the specific surface area (SSA) of carbon species and the electrode porosity collectively influence Zn deposition behavior within three-dimensional (3D) architectures. A highly nanoporous carbon framework enhances ion transport, while high-SSA carbon particles provide an enlarged electrochemical surface active area. These combined effects promote bottom-up Zn deposition and mitigate Zn loss from material detachment. Leveraging these 3D hosts, the half cell delivers an average coulombic efficiency of 99.5% over 700 cycles (2 mA cm⁻² at 2 mA h cm⁻²) in a conventional electrolyte. Combined experimental and simulation results further reveal a diffusion–reaction competition that governs Zn plating in 3D scaffolds. Optimizing this interplay provides a broadly applicable strategy for designing robust 3D Zn hosts and advancing practical aqueous energy-storage systems.