Liu Huiqiao, He Yanan, Cao Kangzhe, Wang Shaodan, Jiang Yong, Liu Xiaogang, Huang Ke-Jing, Jing Qiang-Shan, Jiao Lifang
College of Chemistry and Chemical Engineering, Henan Province Key Laboratory of Utilization of Non-Metallic Mineral in the South of Henan, Xinyang Normal University, Xinyang, 464000, China.
Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin, 300071, China.
Small. 2021 Mar;17(10):e2008133. doi: 10.1002/smll.202008133. Epub 2021 Feb 15.
Conversion-alloy sulfide materials for potassium-ion batteries (KIBs) have attracted considerable attention because of their high capacities and suitable working potentials. However, the sluggish kinetics and sulfur loss result in their rapid capacity degeneration as well as inferior rate capability. Herein, a strategy that uses the confinement and catalyzed effect of Nb O layers to restrict the sulfur species and facilitate them to form sulfides reversibly is proposed. Taking Sb S anode as an example, Sb S and Nb O are dispersed in the core and shell layers of carbon nanofibers (C NFs), respectively, constructing core@shell structure Sb S -C@Nb O -C NFs. Benefiting from the bi-functional Nb O layers, the electrochemical reversibility of Sb S is stimulated. As a result, the Sb S -C@Nb O -C NFs electrode delivers the rapidest K-ion diffusion coefficient, longest cycling stability, and most excellent rate capability among the controlled electrodes (347.5 mAh g is kept at 0.1 A g after 100 cycles, and a negligible capacity degradation (0.03% per cycle) at 2.0 A g for 2200 cycles is delivered). The enhanced K-ion storage properties are also found in SnS -C@Nb O -C NFs electrode. Encouraged by the stimulated reversibility of Sb S and SnS anodes, other sulfides with high electrochemical performance also could be developed for KIBs.
用于钾离子电池（KIBs）的转化型合金硫化物材料因其高容量和合适的工作电位而备受关注。然而，缓慢的动力学和硫损失导致其容量迅速退化以及倍率性能较差。在此，提出了一种利用NbO层的限制和催化作用来限制硫物种并促进其可逆形成硫化物的策略。以SbS阳极为例，将SbS和NbO分别分散在碳纳米纤维（CNFs）的核层和壳层中，构建核壳结构的SbS-C@NbO-CNFs。受益于双功能的NbO层，SbS的电化学可逆性得到激发。结果，SbS-C@NbO-CNFs电极在受控电极中具有最快的K离子扩散系数、最长的循环稳定性和最优异的倍率性能（在0.1 A g下100次循环后保持347.5 mAh g，在2.0 A g下2200次循环时容量退化可忽略不计（每循环0.03%））。在SnS-C@NbO-CNFs电极中也发现了增强的K离子存储性能。受SbS和SnS阳极激发的可逆性的鼓舞，其他具有高电化学性能的硫化物也可用于开发KIBs。
