Synergetic Effect of Ru and NiO in the Electrocatalytic Decomposition of Li 2 CO 3 to Enhance the Performance of a Li-CO 2 /O 2 Battery

作者：Pengfang Zhang, Junyu Zhang, Tian Sheng, Yanqiu Lü, Zu‐Wei Yin, Yuyang Li, Xinxing Peng, Yao Zhou, Jun‐Tao Li, Yijin Wu, Jin‐Xia Lin, Binbin Xu, Ximing Qu, Ling Huang, Shi‐Gang Sun · 发表于：ACS Catalysis · 年份：2019 · DOI：10.1021/acscatal.9b04138 · 被引用次数：147 · 研究领域：Advancements in Battery Materials、Advanced Battery Materials and Technologies、Extraction and Separation Processes

Li 2 CO 3 is the cathodic discharge product of a Li-CO 2 /O 2 battery and is difficult to electrochemically decompose. The accumulation of Li 2 CO 3 leads to battery degradation and results in a short lifespan. Herein, a carbon nanotube supported Ru/NiO@Ni catalyst (Ru/NiO@Ni/CNT) is synthesized with Ru nanoparticles (∼2.5 nm) anchored on the surface of core–shell structure NiO@Ni nanoparticles (∼17 nm). We found strong interfacial interactions between Ru nanoparticles and NiO. XRD and XPS analysis revealed that the presence of Ru could protect the Ni species from being deeply oxidized while the NiO species could modify the local electronic structure of Ru, inducing a higher oxidation state. When such a Ru/NiO@Ni/CNT catalyst is used as a cathode in Li-CO 2 /O 2 (v:v = 4:1) batteries, a long cycling life of 105 cycles at a cutoff capacity of 1000 mAh g –1 with an overpotential as low as 1.01 V was achieved, which is significantly better than 75 and 44 cycles with Ru/CNT and NiO@Ni/CNT catalysts, respectively, and confirms the strong synergetic effect between the Ru and NiO species in the electrocatalytic decomposition of Li 2 CO 3 . Density functional theory (DFT) calculations of the electrochemical decomposition of Li 2 CO 3 with the assistance of RuO 2 indicates that the formation of O 2 is the rate-determining step. In addition, the formation and decomposition process of Li 2 CO 3 was illuminated at a molecular level by in situ FTIR spectroscopy with Ru/NiO@Ni/CNT catalyst...