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

摘要

Zn metal anodes, the key to aqueous zinc-based energy storage, areplagued by dendrites and sluggish kinetics, which are closely related tothe Zn plating process and restricted charge carriers exchange. Herein,a strategy of charge carriers enrichment during Zn plating by employingzincophilic carbon nanotubes (CNTs) on Zn electrodes for dendrite-freeZn anodes under ultrahigh current density is reported. The CNTs enablean electric double layer to effectively facilitate the enrichment of chargecarriers and the refinement of the electric field distribution at the CNTs–Zn interface, displaying unique advantages in enhancing Zn2+ transferdynamics and planar Zn deposition. The extra capacitive interfacialprocess boosts Zn deposition kinetics to afford ultrahigh-rate Zn platingand stripping by decreasing both electrochemical polarization and concentrationpolarization. As a consequence, reversible Zn stripping andplating at an ultrahigh current density of 50 mA cm~（?2） and a remarkabledischarging depth of 97% are reached. Zn ion hybrid supercapacitorsachieve stable cycling at 50 mA cm~（?2） for 10 000 cycles. This paper offersmechanistic insight for advanced Zn anodes supporting high-ratecharge/discharge with large capacities and enlightens the design of metalanodes.