Li Mai, Liu Hui, Li Huifang, Luan Deyan, Liu Zhiming, Lou Xiong Wen David
College of Electromechanical Engineering, Shandong Engineering Laboratory for Preparation and Application of High-Performance Carbon Materials, Qingdao University of Science & Technology, Qingdao, 266061, P.R. China.
Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, P.R. China.
Angew Chem Int Ed Engl. 2025 May 26;64(22):e202503174. doi: 10.1002/anie.202503174. Epub 2025 Apr 2.
Rational design of the coordination environment of single-atom catalysts (SACs) can enhance their catalytic activity, which is of great significance for high-loading and lean-electrolyte lithium-sulfur (Li─S) batteries. Inspired by the Lewis acid-base theory, we design a unique coordination environment for constructing electron-deficient Co SACs on carbon nanotubes (named as CNT@f-CoNC), which function as a Lewis acid, to enhance the chemisorption and catalytic activity towards polysulfides (Lewis base). Compared with porphyrin-like Co SACs, electron-deficient Co SACs (Lewis acid) exhibit much stronger binding affinity towards polysulfides (Lewis base) and a significantly lower energy barrier of the rate-determining step in the sulfur reduction reaction. As expected, even with a high sulfur loading (6.9 mg cm) and lean electrolyte to sulfur (E/S) ratio (4.0 µL mg), the areal capacity still reaches 7.7 mAh cm. Moreover, a 1.6 Ah-class pouch cell is successfully assembled under the harsh conditions and delivers an energy density of 422 Wh kg. This work provides novel insights into enhancing the electrochemical performance of Li─S batteries by modulating the local electronic density of metal sites through the rational design of the coordination environment.
合理设计单原子催化剂（SAC）的配位环境可以提高其催化活性，这对于高负载和贫电解质锂硫（Li-S）电池具有重要意义。受路易斯酸碱理论的启发，我们设计了一种独特的配位环境，用于在碳纳米管上构建缺电子的钴单原子催化剂（命名为CNT@f-CoNC），其作为路易斯酸，以增强对多硫化物（路易斯碱）的化学吸附和催化活性。与类卟啉钴单原子催化剂相比，缺电子的钴单原子催化剂（路易斯酸）对多硫化物（路易斯碱）表现出更强的结合亲和力，并且在硫还原反应中速率决定步骤的能垒显著更低。正如预期的那样，即使在高硫负载（6.9 mg cm）和贫电解质与硫的比例（E/S = 4.0 μL mg）下，面积容量仍达到7.7 mAh cm。此外，在苛刻条件下成功组装了一个1.6 Ah级软包电池，其能量密度为 422 Wh kg。这项工作通过合理设计配位环境来调节金属位点的局部电子密度，为提高锂硫电池的电化学性能提供了新的见解。
