Structurally modified V₂O₅based extrinsic pseudocapacitor

Rapidly changing demand on energy storage systems makes it essential to redesign the device architecture and materials required to fabricate the devices. It is crucial to introduce capacitive behaviour in a conventional energy storage device (batteries) to improve the lifetime and power efficiency of the hole energy storage system. The charge storing nature of electrode material primarily depends on particle size, grain size, the electrode's chemical structure, and effective diffusion lengths for electrolytes within the electrode. Here V₂O₅based Li-ion battery electrode is transformed into a Li-ion pseudocapacitive electrode by structural modifications. The modified structures are achieved by optimizing reaction pressure to obtain larger, medium and smaller V₂O₅particles (namely, V₂O₅-L, V₂O₅-M and V₂O₅-S). As a result, the plateau regions in galvanostatic charge-discharge plots and highly intense redox peaks in the CV plots of V₂O₅-L get flattened for V₂O₅-S. Also, the lucrative improvement in rate capabilities and stability for V₂O₅-S indicates induced pseudocapacitance in V₂O₅. Some devices are fabricated with the extrinsic pseudocapacitive material (V₂O₅-S), providing 4.36 mWh cm^-3volumetric energy density with 125 mW cm^-3volumetric power density. The device retains around 95% of its initial capacitance after 10k cycles and holds up to 63% after 25k stability cycles.