Wang Jie

DTT-doped MWCNT coating for checking shuttle effect of lithium-sulfur battery

In order to improve the rate and reversible capacity of lithium-sulfur (Li-S) battery, a reagent of dithiothreitol (DTT) was utilized to check the dissolution and shuttle of long-chain lithium polysulfides (LiPSs) by cutting the disulfide bond (–S–S– bonds) in them. The slurry of DTT-doped multi-walled carbon nanotubes (MWCNTs) was coated on the surface of sulfur cathode as a shield to slice the long-chain LiPSs to short-chain ones for checking the dissolution and migration of LiPSs to lithium anode. The morphology and structure of the electrodes were observed by scanning electron microscopy (SEM). The electrochemical performance was tested by galvanostatic charge-discharge, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The initial discharge capacity of S-DTT- carbon nanotube paper (CNTP) electrode reached 1670 and 949xa0mAh/g at 0.05 and 2xa0C respectively with a coulombic efficiency of over 99%. The electrode maintained a reversible specific capacity of 949xa0mAh/g after 45xa0cycles at 2xa0C. This suggested that the DTT-doped MWCNT coating can restrain shuttle effect and improve the rate and capacity of Li-S battery. The S-DTT-CNTP electrode not only accommodates the volume expansion but also provides stable electronics and ions channels.