Monolithic integration of MoS2 quantum sheets on solid electrolyte for self-charging supercapacitor power cell governed by piezo-ionic effect

Piezoelectric-driven self-charging supercapacitor power cells (SCSPCs) emerged as promising energy devices that can simultaneously harvest-, convert-, and store electrical energy in an integrated cell. Recent research efforts have been focused on (i) understanding the fundamental mechanism of the energy transduction process and (ii) improving the self-charging performances, respectively. Herein, we utilized the piezo-ionic properties of Nafion (solid polyelectrolyte) together with their bi-functional properties (separator cum electrolyte) in a SCSPC (using MoS2 quantum sheets as energy storage electrodes) and examined their self-charging performance. The exper-iments on the evaluation of piezo-ionic properties of the Nafion polyelectrolyte showed that they can produce a peak-peak voltage of 910 mV due to the generation of Donnan potential. Next, studies on the electrochemical performance of solid state MoS2-Nafion-MoS2 SCSPC revealed that they possess a high capacity/capacitance (0.40 mu Ah cm(-2)/1.81 mF cm(-2)), energy density (252 mu J cm(-2)), and long-cycle life. Finally, studies on the self -charging characteristics of the MoS2-Nafion-MoS2 SCSPC show that they can self-charge upto 243 mV with su-perior electro-mechanical stability. Collectively, the piezo-ionic mediated energy transfer process in the self -charging process of the MoS2-Nafion-MoS2 SCSPC is explained in accordance with the Nernst theory for a two-dimensional system. This work opens-up a fresh paradigm towards the development of all-solid-state SCSPCs utilizing solid electrolytes.