Engineering the composition of SnMnS solid solution nanoparticles for sustainable energy storage.

Driven by the growing need for cost-effective and efficient energy storage devices, numerous efforts have been devoted to the sustainable design and development of electrode materials. To meet this demand, we propose tin sulfide-manganese sulfide solid solution nanoparticle-based electrodes as a viable solution, operating in conjunction with a cytocompatible phosphate-buffered saline solution as the electrolyte. In this study, the SnMnS solid solution nanoparticles of three different compositions were synthesized using a wet chemical route. After investigating the structural, microstructural, and dielectric properties, the electrochemical performance of the electrode as a function of manganese concentration was evaluated to determine the optimal composition of the solid solution for electrochemical energy storage. Our results highlight the significant potential of tin sulfide-manganese sulfide solid solution nanoparticles at a 20 at% manganese concentration as the optimal composition, which can achieve a specific capacitance of 47.6 mF cm at a current density of 0.05 mA cm and show excellent capacitance retention over 2000 cycles with no observable performance degradation.