Na₃V_1.5Cr_0.5(PO₄)₃/rGO as ultralong-life and high-rate of cathode for aqueous hybrid Zn[sbnd]Na battery

Aqueous zinc ion batteries, known for their intrinsic safety and cost-effectiveness, are attracting significant interest as promising candidates for future energy storage devices. Na₃V₂(PO₄)₃ have been served as optimal cathodes due to its large ion channels, high voltage and fast ion kinetics. Herein, a facile sol-gel route is used to synthesize Na₃V_1.5Cr_0.5(PO₄)₃ nanoparticles that are encapsulated within a conductive graphene matrix, denoted as NVCP/rGO. The NVCP/rGO served as the cathode in aqueous Zn[sbnd]Na hybrid battery. NVCP/rGO exhibits a remarkable capacity of 86.1 mAh·g⁻¹ at 100 mA·g⁻¹ and maintains an average discharge platform of 1.45 V, demonstrating cycling stability with 85.9 % capacity retention after 1000 cycles. It offers excellent high rate capability (78.2 mAh·g⁻¹ at 3000 mA·g⁻¹) and a long lifespan (72.1 % capacity retention after 7000 cycles at 1000 mA·g⁻¹). Moreover, NVCP/rGO demonstrates a stable reversible capacity of 80.4 mAh·g⁻¹, maintaining 95.2 % of its capacity after 600 cycles at 100 mA·g⁻¹, even in the challenging conditions of −15 °C. NVCP/rGO displays remarkable capabilities for rate and cycling performance, making it as a promising candidate for integration into next-generation aqueous hybrid Zn[sbnd]Na battery. Additionally, it displays broad propests in low-temperature electrical energy storage applications.