Improved lithium ion storage performance of Ti3C2Tx MXene@S composite with carboxymethyl cellulose binder

MXenes are regarded as promising electrode materials for lithium-ion batteries owing to their high elec-trical conductivity and two-dimensional structure but suffer from low intrinsic specific capacities. In this study, we fabricate sulphur-doped multilayer Ti3C2Tx MXenes via calcination and annealing using sub-limed sulphur as the sulphur source. After sulphur doping, the interlayer spacing of Ti3C2Tx increases, which is favourable for Li-ion insertion. The Ti3C2Tx MXene@S composite exhibits excellent electrochem-ical performance. A high reversible specific capacity of 393.8 mAh g-1 at a current density of 100 mA g-1 after 100 cycles is obtained. Additionally, a negative fading phenomenon is observed when the specific capacity increases to 858.9 mAh g-1 after 2550 cycles at 1 A g-1 and to 322.2 mA h g-1 after 3600 cycles at 5 A g-1 from the initial 267.3 mAh g-1. We systematically investigate the effects of two different bin-ders (polyvinylidene difluoride and carboxymethyl cellulose, hereinafter abbreviated as PVDF and CMC, respectively) on the electrochemical performance of the Ti3C2Tx MXene@S composite and discovered that the electrode using the CMC binder exhibits better lithium-ion storage performance than that using the PVDF binder, which is attributed to the lower charge transfer resistance, higher ion diffusivity, and enhanced adhesion force.(c) 2023 Elsevier Inc. All rights reserved.