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 Ni3S2/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 Ni3S2/Ni composites were analyzed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD), respectively. A Ni3S2/Ni composite, which consisted of submicrometer grains with size in the range of 0.2-2 mu m, was obtained. Galavostatic battery testing shows that the submicrometer Ni3S2/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 (similar to 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) (similar to 6 C). The performances may benefit from their miscellaneous submicrometer structures and subsequently formed tremella-like structures during discharge/charge cycles.