Low-temperature dendrite-free Zn metal battery catalyzed by TiN-enhanced diffusion layer

Abstract

Aqueous zinc metal batteries (AZMBs) are promising for large-scale energy storage due to their intrinsic safety and cost effectiveness. However, the cycling stability of metallic Zn anode under low temperature surroundings is severely hindered by harmful hydrogen evolution reaction (HER) and uncontrollable dendrite growth, which is ascribed to sluggish desolvation kinetics of hydrated [Zn(H₂O)_x]²⁺ and blocked Zn²⁺ diffusion kinetics. Herein, the strategy of “adsorption-sieving-catalysis” is initially proposed and the titanium nitride anchored on self-assembly porous reduced graphene oxide (TiN@RGO) as functional modulator is constructed on the surface of Zn anode. The abundant electrocatalytic sites on sieving pores significantly enhance interfacial desolvation, thereby accelerating Zn²⁺ diffusion kinetics for dendrite-free plating. Consequently, TiN@RGO modified Zn delivers a long-term stripping/plating lifespan above 2600 h at 0.5 mA cm⁻² and maintains reversible stability of 500 h at 2 mA cm⁻² even under low temperature of 0 °C. Decreasing to as low as −8 °C, stable overpotential around 130 mV without any short-circuit is achieved. The coupled full cell with MnO₂ presents a high capacity retention of 72 % after 1000 cycles at 1.0 A g⁻¹ at low temperature of 0 °C, providing new insights for the rational design of efficient LT-AZMBs.