Syntheses and Energy Storage Applications of MxSy (M = Cu, Ag, Au) and Their Composites: Rechargeable Batteries and Supercapacitors

The development of novel materials to improve energy storage efficiencies is essential to satisfy ever-increasing energy demands. MxSy (M = Cu, Ag, Au) and their composites offer opportunities and enormous prospects in energy storage due to their extraordinary electrochemical properties, which promote promising energy storage characteristics in terms of stability, energy and power density, lifetime, etc. Recent developments of MxSy (M = Cu, Ag, Au) and their composites with various morphologies have received considerable attention. Multidimensional morphologies of MxSy (M = Cu, Ag, Au) and their composites have enriched charge-storage and electron-transport abilities. This review provides a detailed account of the synthetic strategies based on sulfur sources (i.e., inorganic sulfur sources, organosulfur sources, and other sulfur sources), which dictate the morphologies of nanosized MxSy (M = Cu, Ag, Au) and their composites. Notably, nanostructured silver sulfide can be prepared from the bulk to nanoscale. Moreover, the electrochemical applications of these materials for lithium-ion batteries, sodium-ion batteries, lithium-sulfur batteries, and supercapacitors are summarized. Finally, future perspectives on the development challenges and major opportunities for MxSy (M = Cu, Ag, Au) and their composites, which must be overcome to achieve further improvements in electrochemical performance are outlined.