Ultrahigh-Rate Zn Stripping and Plating by Capacitive Charge Carriers Enrichment Boosting Zn-Based Energy Storage

Zn metal anodes, the key to aqueous zinc-based energy storage, are plagued by dendrites and sluggish kinetics, which are closely related to the Zn plating process and restricted charge carriers exchange. Herein, a strategy of charge carriers enrichment during Zn plating by employing zincophilic carbon nanotubes (CNTs) on Zn electrodes for dendrite-free Zn anodes under ultrahigh current density is reported. The CNTs enable an electric double layer to effectively facilitate the enrichment of charge carriers and the refinement of the electric field distribution at the CNTs-Zn interface, displaying unique advantages in enhancing Zn2+ transfer dynamics and planar Zn deposition. The extra capacitive interfacial process boosts Zn deposition kinetics to afford ultrahigh-rate Zn plating and stripping by decreasing both electrochemical polarization and concentration polarization. As a consequence, reversible Zn stripping and plating at an ultrahigh current density of 50 mA cm(-2) and a remarkable discharging depth of 97% are reached. Zn ion hybrid supercapacitors achieve stable cycling at 50 mA cm(-2) for 10 000 cycles. This paper offers mechanistic insight for advanced Zn anodes supporting high-rate charge/discharge with large capacities and enlightens the design of metal anodes.