Co3O4@MWCNT modified separators for Li–S batteries with improved cycling performance

The commercialization of Li–S batteries is hindered by their bottlenecks especially the ‘shuttle effect’ and the corrosion of the lithium anodes. To alleviate the two important problems simultaneously and improve the service life of Li–S batteries, we modified commercial separators with Co3O4@MWCNT (carboxylate-terminated multi-walled carbon nanotube)(nano Co3O4@MWCNT modified DKJ-14 abbreviation NMD) for the batteries to improve the electrochemical performance of the unmodified batteries. The nano Co3O4 can catalyze the conversion of polysulfides, and MWCNT can reduce the charge transfer resistance of Li–S batteries. The NMD separators can physically barrier and catalytically convert polysulfides into Li2S, prevent the corrosion of anode, and suppress the ‘shuttle effect’ in the batteries. In addition, the charge transfer resistance of the modified separators is low. The Li–S battery with a NMD separator has an initial specific capacity of 1007 mAh/g at 1 C, and the capacity of each cycle is only attenuated by 0.068% over 750 cycles. In addition, the lithium anode is uncorroded after 50 cycles at 1 C. The work provides a reference for commercialization of Li–S batteries in the future.