Sharma Vidushi, Datta Dibakar
Department of Mechanical and Industrial Engineering, New Jersey Institute of Technology, Newark, NJ 07103, USA.
Phys Chem Chem Phys. 2021 Mar 11;23(9):5540-5550. doi: 10.1039/d0cp06190e.
Current advancements in battery technologies require electrodes to combine high-performance active materials such as Silicon (Si) with two-dimensional materials such as transition metal carbides (MXenes) for prolonged cycle stability and enhanced electrochemical performance. More so, it is the interface between these materials, which is the nexus for their applicatory success. Herein, the interface strength variations between amorphous Si and Ti3C2Tx MXenes are determined as the MXene surface functional groups (Tx) are changed using first principles calculations. Si is interfaced with three Ti3C2 MXene substrates having surface -OH, -OH and -O mixed, and -F functional groups. Density functional theory (DFT) results reveal that completely hydroxylated Ti3C2 has the highest interface strength of 0.6 J m-2 with amorphous Si. This interface strength value drops as the proportion of surface -O and -F groups increases. Additional analysis of electron redistribution and charge separation across the interface is provided for a complete understanding of underlying physico-chemical factors affecting the surface chemistry and resultant interface strength values. The presented comprehensive analysis of the interface aims to develop sophisticated MXene based electrodes by their targeted surface engineering.
当前电池技术的进展要求电极将高性能活性材料（如硅（Si））与二维材料（如过渡金属碳化物（MXenes））相结合，以实现更长的循环稳定性和增强的电化学性能。更重要的是，这些材料之间的界面是它们应用成功的关键。在此，使用第一性原理计算确定了随着MXene表面官能团（Tx）的变化，非晶硅与Ti3C2Tx MXenes之间的界面强度变化。硅与具有表面-OH、-OH和-O混合以及-F官能团的三种Ti3C2 MXene基底相接。密度泛函理论（DFT）结果表明，完全羟基化的Ti3C2与非晶硅的界面强度最高，为0.6 J m-2。随着表面-O和-F基团比例的增加，该界面强度值下降。还对界面上的电子重新分布和电荷分离进行了额外分析，以全面了解影响表面化学和所得界面强度值的潜在物理化学因素。所呈现的对界面的综合分析旨在通过有针对性的表面工程开发基于MXene的先进电极。
