Yang Chao, Guo Kunkun, Yuan Dingwang, Cheng Jianli, Wang Bin
College of Materials Science and Engineering, Hunan University, Changsha 410082, People's Republic of China.
Sichuan Research Center of New Materials, Chengdu, Sichuan 610200, People's Republic of China.
J Am Chem Soc. 2020 Apr 15;142(15):6983-6990. doi: 10.1021/jacs.9b12868. Epub 2020 Apr 3.
First-principles density functional theory calculations are first used to study possible reaction mechanisms of molybdenum carbide (MoC) as cathode catalysts in Li-CO batteries. By systematically investigating the Gibbs free energy changes of different intermediates during lithium oxalate (LiCO) and lithium carbonate (LiCO) nucleations, it is theoretically demonstrated that LiCO could be stabilized as the final discharge product, preventing the further formation of LiCO. The surface charge distributions of LiCO adsorbing onto catalytic surfaces are studied by using Bader charge analysis, given that electron transfers are found between LiCO and MoC surfaces. The catalytic activities of catalysts are intensively evaluated toward the discharge and charge processes by calculating the electrochemical free energy diagrams to identify the overpotentials. Our studies promote the understanding of electrochemical processes and shed more light on the design and optimization of cathode catalysts for Li-CO batteries.
第一性原理密度泛函理论计算首次用于研究碳化钼（MoC）作为锂-二氧化碳电池阴极催化剂的可能反应机理。通过系统研究草酸锂（Li₂C₂O₄）和碳酸锂（Li₂CO₃）成核过程中不同中间体的吉布斯自由能变化，从理论上证明了Li₂C₂O₄可以作为最终放电产物稳定下来，从而阻止Li₂CO₃的进一步形成。考虑到在Li₂C₂O₄和MoC表面之间发现了电子转移，利用巴德电荷分析研究了Li₂C₂O₄吸附在催化表面上的表面电荷分布。通过计算电化学自由能图来确定过电位，从而深入评估催化剂对放电和充电过程的催化活性。我们的研究促进了对电化学过程的理解，并为锂-二氧化碳电池阴极催化剂的设计和优化提供了更多启示。
