Carbon enhanced nucleophilicity of Na3V2(PO4)3: A general approach for dendrite-free zinc metal anodes

Abstract

Zincophilic property and high electrical conductivity are both very important parameters to design novel Zn anode for aqueous Zn-ion batteries (AZIBs). However, single material is difficult to exhibit zincophilic property and high electrical conductivity at the same time. Herein, originating from theoretical calculation, a zincophilic particle regulation strategy is proposed to address these limitations and carbon coated Na3V2(PO4)3 is taken as an example to be a protective layer on zinc metal (NVPC@Zn). Na3V2(PO4)3 (NVP) is a common cathode material for Zn-ion batteries, which is zincophilic. Carbon materials not only offer an electron pathway to help Zn deposition onto NVPC surface, but also enhance the zinc nucleophilicity of Na3V2(PO4)3. Hence, this hybrid coating layer can tune zinc deposition and resist side reactions such as hydrogen generation and Zn metal corrosion. Experimentally, a symmetrical battery with NVPC@Zn electrode displays highly reversible plating/stripping behavior with a long cycle lifespan over 1800 h at 2 mA cm−2, much better than carbon and Na3V2(PO4)3 solely modified Zn electrodes. When the Na3V2(PO4)3 is replaced with zincophobic Al2O3 or zincophilic V2O3, the stability of the modified zinc anodes is also prolonged. This strategy expands the option of zincophilic materials and provides a general and effective way to stabilize the Zn electrode.