Yi Yikun, Li Hongping, Chang Honghong, Yang Pu, Tian Xiaolu, Liu Pei, Qu Long, Li Mingtao, Yang Bolun, Li Huaming, Zhu Wenshuai, Dai Sheng
Shaanxi Key Laboratory of Energy Chemical Process Intensification, School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, 710049, P.R. China.
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, P.R. China.
Chemistry. 2019 Jun 18;25(34):8112-8117. doi: 10.1002/chem.201900884. Epub 2019 May 21.
Lithium-sulfur (Li-S) batteries have become one of the most promising candidates as next-generation batteries, owing to their high specific capacity, low cost, and environmental benignity. Although many strategies have been proposed to restrain the shuttle of lithium polysulfides (LiPSs) through physical trapping and chemical binding, the sluggish kinetics of PS conversion still degrade the capacity, rate, and cycling performance of Li-S batteries. Herein, a novel kind of few-layer BN with engineered nitrogen vacancies (v-BN) has been developed as a cathode matrix for Li-S batteries. The positive vacancies in the BN nanosheets not only promote the immobilization and conversion of LiPSs, but also accelerate the lithium ion diffusion in cathode electrodes. Compared with pristine BN, the v-BN cathodes exhibit higher initial capacities from 775 mA h g to 1262 mA h g at 0.1 C and a high average coulombic efficiency of over 98 % during 150 cycles. Upon increasing the current density to 1 C, the cell still preserves a capacity of 406 mA h g after 500 cycles, exhibiting a capacity decay of only 0.084 % per cycle. The new vacancy-engineered material provides a promising method for achieving excellent performance in Li-S batteries.
锂硫（Li-S）电池因其高比容量、低成本和环境友好性，已成为最有前景的下一代电池候选者之一。尽管已经提出了许多策略来通过物理捕获和化学结合来抑制多硫化锂（LiPSs）的穿梭，但多硫化物转化的缓慢动力学仍然会降低Li-S电池的容量、倍率和循环性能。在此，一种新型的具有工程氮空位的少层氮化硼（v-BN）已被开发用作Li-S电池的正极基体。氮化硼纳米片中的正空位不仅促进了LiPSs的固定和转化，还加速了锂离子在正极中的扩散。与原始氮化硼相比，v-BN正极在0.1 C下的初始容量从775 mA h g提高到1262 mA h g，并且在150次循环中具有超过98%的高平均库仑效率。当电流密度增加到1 C时，电池在500次循环后仍保持406 mA h g的容量，每循环的容量衰减仅为0.084%。这种新的空位工程材料为在Li-S电池中实现优异性能提供了一种有前景的方法。
