Thermally Optimized Silver Dimolybdate Nanostructures-Based Pseudocapacitive Supercapacitors: From Coin-Cell Evaluation to Prototype Device Applications

The growing demand for fast, durable energy storage has intensified interest in pseudocapacitive electrodes that offer rapid redox kinetics and structural stability. In this work, a solvent-free thermal decomposition strategy is employed for the scalable synthesis of phase-pure monoclinic β-Ag2Mo2O7 silver dimolybdate nanostructures. Systematic optimization of thermal dwell time enables controlled phase formation and enhanced electrochemical performance. The optimized electrode exhibits a high specific capacitance of 937.5 Fg–1 at 1 Ag–1 and retains 92.8% of its initial capacitance after 10000 cycles. Kinetic analysis using Dunn’s method reveals a hybrid charge-storage mechanism arising from coupled diffusion-controlled redox reactions and surface-dominated pseudocapacitive processes associated with Ag0/Ag+ and Mo5+/Mo6+ couples. Symmetric and asymmetric coin-cell devices operate stably up to 1.5 V, delivering an energy density of 82 Wh kg–1 at 1172 W kg–1 with high Coulombic efficiency. Practical feasibility is demonstrated by powering an Arduino-based temperature sensor using series-connected asymmetric cells. These results demonstrate that thermally engineered β-Ag2Mo2O7 silver dimolybdate nanostructures are scalable and effective pseudocapacitive electrodes for high-performance supercapacitor applications.