Han Kun, Ji Yuhuan, Hu Qianku, Wu Qinghua, Li Dandan, Zhou Aiguo
Henan Key Laboratory of Materials on Deep-Earth Engineering, School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China.
Phys Chem Chem Phys. 2024 Jul 3;26(26):18030-18040. doi: 10.1039/d4cp01928h.
The advancement of anode materials for achieving high energy storage is a crucial topic for high-performance Li-ion batteries (LIBs). Here, first-principles calculations were used to conduct a thorough and systematic investigation into lithium storage properties of MXenes with new S functional groups as LIB anode materials. Density of states, diffusion energy barriers, open circuit voltages and storage capacities were calculated to comprehensively evaluate the lithium storage properties of S-functionalized MXenes. Based on the computational results, TiCS and VCS were selected as excellent candidates from ten MCS MXenes. The diffusion energy barriers of MCS within the range of 0.26-0.32 eV are lower than those of MCO and MCF, indicating that MCS anodes exhibit faster charge/discharge rates. By examining the stable crystal structures and comparing atomic positions before and after Li adsorptions, structural phase transitions during Li-ion adsorptions could happen for nearly all MCS MXenes. The phase transitions predicted were directly observed using molecular dynamic simulations. The cycle stability, storage capacity and other lithium storage properties were enhanced by the reversible structural phase transition.
开发用于实现高能量存储的阳极材料是高性能锂离子电池（LIB）的一个关键课题。在此，我们使用第一性原理计算对具有新型S官能团的MXenes作为LIB阳极材料的储锂性能进行了全面而系统的研究。计算了态密度、扩散能垒、开路电压和存储容量，以全面评估S官能化MXenes的储锂性能。基于计算结果，从十种MCS MXenes中选出TiCS和VCS作为优秀候选材料。MCS的扩散能垒在0.26-0.32 eV范围内，低于MCO和MCF，这表明MCS阳极具有更快的充/放电速率。通过研究稳定的晶体结构并比较锂吸附前后的原子位置，几乎所有MCS MXenes在锂离子吸附过程中都可能发生结构相变。利用分子动力学模拟直接观察到了预测的相变。可逆的结构相变增强了循环稳定性、存储容量和其他储锂性能。
