3-9. Material mechanical and electrochemical high-throughput design: new two-dimensional transition metal carbides

Ruifeng Zhang

School of Materials Science and Engineering, Beihang University

Abstract: The new two-dimensional transition metal carbides (MXenes) are considered to have broad application prospects in many fields such as energy storage, electrocatalysis, water purification and electromagnetic shielding due to their excellent conductivity, hydrophilicity, and ion adsorption properties. In previous studies, researchers have focused on unilateral stabilities and electrochemical properties of ideal surface configurations, ignoring the effects of specific service conditions (such as strain and solution environment). It is well known that the external environment may seriously affect the performance of materials, therefore it is of great practical significance to comprehensively consider the synergistic effect of various factors on its performance. At the same time, MXenes' rich chemical diversity is also very beneficial for us to evaluate its performance using high-throughput solving techniques. In view of the above situation, using the high-throughput automatic solution technology developed by our group, we deeply explored the effects of surface functional groups and metal composition on the thermodynamic stabilities, mechanical strengths and electrochemical properties of the two-dimensional material MXenes. It is found that the thermodynamic stability, mechanical properties and electrochemical properties of MXene show periodic changes with the change of metal valence electron numbers. As the proportion of surface F/O functional groups increases, the mechanical parameters such as elastic modulus and mechanical strength gradually decrease. Under multiple load stresses, MXene still maintains good electrochemical performance, while the stress state can flexibly and efficiently modulate the migration path of Li. The bare MXene has better overall electrochemical performance, while the MXene with full oxygen functional group has better mechanical properties. The above findings provide theoretical guidance for MXene's future experimental design.

Keywords: High-throughput solving technique; MXenes; Mechanochemical coupling

材料力学和电化学高通量设计：新型二维过渡金属碳化物

张瑞丰

北京航空航天大学材料科学与工程学院

摘要：新型二维过渡金属碳化物（MXene）因其优异的导电性、亲水性、离子吸附性等性质，被认为在能量储存、电催化、水净化、电磁屏蔽等诸多领域具有广阔的应用前景。在以往研究中，研究人员往往侧重于理想表面构型单方面稳定性及电化学性质研究，而忽略具体服役条件（诸如应变、溶液环境等）所造成的影响。而众所周知，外在环境将可能会严重影响材料的性能，因此综合考虑多方面因素间协同效应对其性能的影响具有重要的实际意义。同时，MXene丰富的化学多样性也非常有利于我们使用高通量求解技术对其性能进行评估。针对以上现状，运用我们组开发的高通量自动求解技术，我们深入探索了二维材料MXene中表面官能团及金属组成对其热力学稳定性、力学强度及电化学性质的影响。研究发现，MXene的热力学稳定性、力学性质及电化学性质均随着金属价电子数的变化呈现出周期性的变化。随着表面F/O官能团比例的增加，弹性模量及力学强度等力学参量逐渐减小。在多重载荷应力下，MXene仍能保持良好的电化学性能，而应力状态则可以灵活有效地调制Li的迁移路径。裸露的MXene具有较好的综合电化学性能，而满吸附氧官能团的MXene则具有更好的力学性能。以上发现对MXene的未来实验设计提供了理论指导。

关键词：高通量求解技术；MXenes；力化耦合