Investigation of synthesis conditions for (NH₄)₀.₅V₂O₅ and its potential application in potassium-ion batteries (KIBS)

Potassium-ion batteries (KIBs) have gained considerable attention as promising alternatives to lithium-ion batteries (LIBs), due to the abundant resource of potassium, low cost, and low redox potential. Developing electrode materials with stable structure and reversible K⁺ intercalation remains a significant challenge. In this study, (NH₄)₀,₅V₂O₅ was synthesized via hydrothermal method under various conditions to investigate the effects of temperature and duration on its structure and electrochemical performance. The materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Electrochemical behavior was evaluated through cyclic voltammetry (CV), cycling stability, and Coulombic efficiency. The optimized (NH₄)₀.₅V₂O₅ sample revealed reversible K⁺ intercalation with a specific capacity of 130 mAh·g⁻¹ at C/10 over a voltage window of 1.5–4.0 V (vs. K⁺/K), demonstrating its potential as a high-performance cathode material for KIBs.