Aqueous polysulfide/iodide redox flow batteries are attractive for scalable energy storage due to their high energy density and low cost. However, their energy efficiency and power density are usually limited by poor electrochemical kinetics of the redox reactions of polysulfide/iodide ions on graphite electrodes, which has become the main obstacle for their practical applications. Here, CoS₂/CoS heterojunction nanoparticles with uneven charge distribution, which are synthesized in situ on graphite felt by a one-step solvothermal process, can significantly boost electrocatalytic activities of I⁻/I₃⁻ and S²⁻/S_x²⁻ redox reactions by improving absorptivity of charged ions and promoting charge transfer. The polysulfide/iodide flow battery with the graphene felt-CoS₂/CoS heterojunction can deliver a high energy efficiency of 84.5% at a current density of 10 mA cm⁻², a power density of 86.2 mW cm⁻² and a stable energy efficiency retention of 96% after approximately 1000 h of continuous operation.

Polychrome silver nanoparticles have been prepared by a soft solution approach under microwave irradiation from a solution of silver nitrate (AgNO₃) in the presence of poly(N-vinyl-2-pyrrolidone) without any other reducing agent. Different morphologies of silver colloids with charming colors could be obtained using different solvents as the reaction medium. The structures of the silver colloids were determined by X-ray powder diffraction. UV-Vis spectroscopy was used to follow the reaction process and to characterize the optical properties of the resultant silver colloids. The influence of the solvent on the morphology of silver was investigated.

CoNi₂S₄/graphene nanocomposite electrodes exhibit excellent pseudocapacitance behavior enhanced by synergistic effect, demonstrating the nanocomposite's promise as an electrode material for high-performance supercapacitors.