ZnV2O4-Textured Carbon Composite Contacting a ZIF-8 MOF Layer for a High Performance Non-Aqueous Zinc-Ion Battery

Non-aqueous zinc-ion battery (ZIB) comprising a zinc vanadate@textured carbon (ZnV2O4@TC) composite cathode and Zn-anode demonstrates an improved Zn(II)-ion storage response, in terms of cyclability (230 mAh g(-1) after 200 cycles, 84.9% retention) and rate capability compared to pristine ZnV2O4 (175 mAh g(-1) after 200 cycles, 45.4% retention). TC reduces the aggregation of ZnV2O4 nanoparticles, allows abundant interaction with electrolyte, affords short ion diffusion pathways, serves as electrically conducting interconnects, and buffers the volume alterations thus imparting rapid kinetics and improved cycling stability. This performance is even better by the inclusion of a ZIF-8 metal-organic framework (MOF) layer at the separator, facing the cathode. ZIF-8 due to its nanoporous structure encompassing Zn-N based polyhedral clusters, efficiently confines Zn(II) ions at cathode during discharge and allows their facile diffusion through its open channels during charge thus maximizing Zn(II) ion storage capacity and reversibility and its highly crystalline robust structure also enhances the ZIB durability. This achievement is in line with the development of cost-effective, easily implementable nonaqueous ZIB that avoids the issues associated with aqueous electrolyte of limited potential stability window, corrosion of current collectors over time, and cell degradation and also offers long term stability and capacity.