Excellent electrochemical application of Ni-based hydroxide/biomass porous carbon/sulfur composite cathode on lithium-sulfur batteries

In order to avoid more release of polysulfides into electrolyte, a biomass porous carbon (PC) derived from nodus nelumbinis rhizomatis (NNR) and a network of nickel nitrate hydroxide (Ni 3 (NO 3 ) 2 (OH) 4 , NNH) were firstly utilized as a composite cathode for lithium-sulfur (Li-S) batteries. The NNH/PC/S composite prepared by a mesh-like NNH layer coating in situ on the surface of porous carbon/sulfur composite exhibits an excellent electrochemical performance. The discharge specific capacity is up to 1203.5 mA h g −1 for the initial cycle at 0. 5 C and maintains 521.3 mA h g −1 after 700 cycles. As the current rate is as high as 5 C, the battery with NNH/PC/S cathode still guarantees a sufficient output in specific capacity of 583.9 mA h g −1 . Besides the better conductivity and the accommodation for sulfur from the NNR-derived porous carbon, the coating of the mesh-like NNH layer also plays a critical role in improving the cycling properties by providing a strong adsorption by Ni-S bond and more active sites for redox reactions, and thus suppressing the dissolution of polysulfides .