Arginine modification of hybrid cobalt/nitrogen Ti3C2Tx MXene and its application as a sulfur host for lithium-sulfur batteries
Miao Zhang, Kaiyu Zhang, Wei Wei, Hongxin Yuan, Jingjing Chang, Yue Hao
Abstract
The shuttling effect of lithium polysulfides (LiPSs) is one of the challenges facing the commercialization, which leads to a significant capacity degradation. This paper proposes a novel method to promote polysulfide transformation by employing arginine to regulate the layer spacing of cobalt-nitrogen doped Ti3C2Tx MXene (Co-N@Ti3C2Tx-Arg). The results revealed that arginine effectively extended the interlayer spacing and promoted the homogeneous dispersion of Co and N atoms, thus endowing the sulfur host with a high catalytic activity during the charging and discharging processes. The extended interlayer spacing increased the specific surface area and captured sufficient LiPSs for subsequent catalytic conversions, while the Co and N doping on the surface of Ti3C2Tx significantly promoted the rapid conversion of the LiPSs to Li2S. Therefore, the S cathode coated with Co-N@Ti3C2Tx-Arg exhibited an excellent cycling stability with a low-capacity fading rate of 0.083% over 200 cycles in addition to a high reversible capacity of 1,365.4 mAh g-1 at 0.1 C.