Heterostructured CuCo<sub>2</sub>S<sub>4</sub>-Co<sub>9</sub>S<sub>8</sub> Nanosheets as Freestanding Cathodes for Flexible Fiber-Shaped Li-CO<sub>2</sub> Batteries
Xiaoqi Zhu, Lin Chen, Qisheng Fang, Jianli Cheng, Yuefeng Su, Paula Ratajczak, François Béguin, Bin Wang
Abstract
Li-CO 2 batteries with attractive characteristics of high energy density power supply and carbon dioxide fixation have attracted widespread attention. However, the lack of suitable cathode catalysts and their unsatisfactory electrochemical performance have impeded their development as promising Li-CO 2 batteries for energy storage. Constructing heterojunctions by interfacial engineering to improve performance is considered one of the effective strategies. Herein, heterostructured CuCo 2 S 4 -Co 9 S 8 nanosheets are fabricated by a facile hydrothermal method and employed as efficient cathode catalysts for Li-CO 2 batteries. The construction of heterojunctions by interfacial engineering has proved as an effective strategy to enhance the electrochemical performance of the Li-CO 2 batteries. The delocalized electrons between CuCo 2 S 4 and Co 9 S 8 contribute to a low median charge potential (∼3.6 V), small polarization (0.62 V), high energy efficiency of up to 83%, and outstanding cycle life (480 h) of the CuCo 2 S 4 -Co 9 S 8 cathodes. Meanwhile, as a proof of concept, flexible fiber-shaped Li-CO 2 batteries based on these cathodes are fabricated and demonstrate boosted flexibility adaptability and provide a stable power supply at various bending conditions.