Li Ruilong, Rao Dewei, Zhou Jianbin, Wu Geng, Wang Guanzhong, Zhu Zixuan, Han Xiao, Sun Rongbo, Li Hai, Wang Chao, Yan Wensheng, Zheng Xusheng, Cui Peixin, Wu Yuen, Wang Gongming, Hong Xun
Center of Advanced Nanocatalysis (CAN), Hefei National Laboratory for Physical Sciences at the Microscale, Department of Applied Chemistry, University of Science and Technology of China, Hefei, Anhui, China.
Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
Nat Commun. 2021 May 25;12(1):3102. doi: 10.1038/s41467-021-23349-9.
Lithium-sulfur batteries show great potential to achieve high-energy-density storage, but their long-term stability is still limited due to the shuttle effect caused by the dissolution of polysulfides into electrolyte. Herein, we report a strategy of significantly improving the polysulfides adsorption capability of cobaltous oxide by amorphization-induced surface electronic states modulation. The amorphous cobaltous oxide nanosheets as the cathode additives for lithium-sulfur batteries demonstrates the rate capability and cycling stability with an initial capacity of 1248.2 mAh g at 1 C and a substantial capacity retention of 1037.3 mAh g after 500 cycles. X-ray absorption spectroscopy analysis reveal that the coordination structures and symmetry of ligand field around Co atoms of cobaltous oxide nanosheets are notably changed after amorphization. Moreover, DFT studies further indicate that amorphization-induced re-distribution of d orbital makes more electrons occupy high energy level, thereby resulting in a high binding energy with polysulfides for favorable adsorption.
锂硫电池在实现高能量密度存储方面显示出巨大潜力，但由于多硫化物溶解到电解质中引起的穿梭效应，其长期稳定性仍然有限。在此，我们报告了一种通过非晶化诱导表面电子态调制来显著提高氧化钴对多硫化物吸附能力的策略。作为锂硫电池阴极添加剂的非晶氧化钴纳米片表现出倍率性能和循环稳定性，在1C下初始容量为1248.2 mAh g，500次循环后仍有1037.3 mAh g的可观容量保持率。X射线吸收光谱分析表明，非晶化后氧化钴纳米片Co原子周围配体场的配位结构和对称性发生了显著变化。此外，密度泛函理论研究进一步表明，非晶化诱导的d轨道重新分布使更多电子占据高能级，从而导致与多硫化物具有高结合能以实现有利吸附。
