Electrodeposition of Nis₃S₂/Ni Composites as High-Performance Cathodes for Lithium Batteries

An alternative electrodeposition technology, which provides an efficient way to complete a better interface contact between electroactive materials and metal foil substrates, was used to prepare Ni 3 S 2 /Ni composites in aqueous solutions contained thiourea (TU). The deposition parameters, such as time and TU concentration, were optimized. Surface morphology, chemical composition, and crystal structure of Ni 3 S 2 /Ni composites were analyzed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD), respectively. A Ni 3 S 2 /Ni composite, which consisted of submicrometer grains with size in the range of 0.2–2 μm, was obtained. Galavostatic battery testing shows that the submicrometer Ni 3 S 2 /Ni 4 composites as cathodes for lithium batteries exhibit a high specific capacity of 338 mAh g –1 at a current density of 0.17 A/g (∼0.6 C), extraordinary capacity retention as well as 95.3% after 100 cycles, and outstanding rate performance, for example, still delivering 180 mAh g –1 at 1.7 A g –1 (∼6 C). The performances may benefit from their miscellaneous submicrometer structures and subsequently formed tremella-like structures during discharge/charge cycles.