Zhang Ning, Zheng Shuangshuang, Zhao Menglong, Lu Yang, Cheng Jinbing, Yang Ya, Peng Tao, Luo Yongsong
Henan Joint International Research Laboratory of New Energy Storage Technology, Key Laboratory of Microelectronics and Energy of Henan Province, School of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000, P. R. China.
Henan International Joint Laboratory of MXene Materials Microstructure, College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061, P. R. China.
Dalton Trans. 2021 Nov 30;50(46):17120-17128. doi: 10.1039/d1dt03108b.
The lithium polysulfide (LiPS) shuttle effect and low redox kinetics are the key problems that hinder performance improvement and prevent achieving the commercial requirements for lithium-sulfur batteries (LSBs), and the reasonable construction of sulfur hosts is one effective strategy to relieve the polysulfide shuttle effect and improve redox kinetics. Herein, N-doped carbon nanocages decorated with homogeneously dispersed TiN nanoparticles (TiN@C NCs) as multifunctional sulfur hosts are designed for superior LSBs. Carbon nanocages provide space to mitigate volume expansion and provide additional physical adsorption to trap the LiPSs. Polar TiN nanoparticles not only exhibit the chemisorption capacity for LiPSs, but also catalyze and promote the conversion of long-chain LiPSs to LiS/LiS in the reduction process as well as the decomposition of LiS in the oxidation reaction, which significantly boosts electron/ion transport and decreases the potential barrier. Therefore, the S/TiN@C NC cathode has an excellent electrochemical capacity of 1485.7 mA h g at 0.1 C. In particular, the cathode demonstrates high capacity reversibility after 500 cycles at 3 C with a retention of about 73.1%, which is equivalent to a slow capacity decay rate of 0.053% per cycle.
多硫化锂（LiPS）穿梭效应和低氧化还原动力学是阻碍锂硫电池（LSB）性能提升并使其无法达到商业要求的关键问题，合理构建硫宿主是缓解多硫化锂穿梭效应并改善氧化还原动力学的一种有效策略。在此，设计了一种以均匀分散的TiN纳米颗粒修饰的N掺杂碳纳米笼（TiN@C NCs）作为多功能硫宿主用于高性能锂硫电池。碳纳米笼提供空间以减轻体积膨胀，并提供额外的物理吸附作用来捕获多硫化锂。极性TiN纳米颗粒不仅对多硫化锂具有化学吸附能力，还能在还原过程中催化并促进长链多硫化锂向Li₂S/Li₂S₂的转化以及在氧化反应中促进Li₂S的分解，这显著提高了电子/离子传输并降低了势垒。因此，S/TiN@C NC阴极在0.1 C下具有1485.7 mA h g的优异电化学容量。特别是，该阴极在3 C下循环500次后表现出高容量可逆性，保留率约为73.1%，相当于每循环0.053%的缓慢容量衰减率。
