New Phosphate Zn₂Fe(PO₄)₂ Cathode Material for Nonaqueous Zinc Ion Batteries with Long Life Span

Phosphate-based cathode materials attract much more attention and are widely used as energy storage materials based on their high economic efficiency and eco-friendly property, their stable potential plateau, and their high thermodynamic stability. A new phosphate family member, Zn₂Fe(PO₄)₂ (ZFP), was successfully explored and synthesized by the scalable high-temperature annealing method, followed by coating a thin carbon layer to optimize the electrotonic conductivity. This obtained ZFP featuring with a tunnel structure can be utilized as a cathode material for Zn²⁺ ion extraction and insertion, in which Zn²⁺ ion diffusion behaviors primarily contribute the specific capacity. Based on the actual reversible capacity of ZFP@C of 73 mA h g^-1, the application for zinc ion batteries (ZIBs) has potential due to its long life span. The electrochemical performance is primarily contributed from the high Zn²⁺ ion diffusion rate and low apparent activation energy. This new explored ZFP can accelerate the development of realizing ZIBs with long life span.