Blow-Spinning Enabled Precise Doping and Coating for Improving High-Voltage Lithium Cobalt Oxide Cathode Performance

作者：Te Tian, Tianwen Zhang, Yi‐Chen Yin, Yi‐Hong Tan, Yong‐Hui Song, Lei‐Lei Lu, Hong‐Bin Yao · 发表于：Nano Letters · 年份：2019 · DOI：10.1021/acs.nanolett.9b04486 · 被引用次数：63 · 研究领域：Advancements in Battery Materials、Advanced Battery Technologies Research、Advanced Battery Materials and Technologies

Lithium cobalt oxide (LiCoO 2 ) possesses an attractive theoretical specific capacity (274 mAh g –1 ) and high discharge voltage (∼4.2 V vs Li + /Li). However, only a half of the theoretical capacity of LiCoO 2 is available in commercialized lithium ion batteries because of the intrinsic structural instability and detrimental interface of LiCoO 2 at the charging voltage over 4.2 V. Here, a facile blow-spinning synthetic method is developed to realize precise doping and simultaneous self-assembly coating of LiCoO 2 particles, achieving a record performance among present LiCoO 2 cathodes. Owing to the spatial confinement effect of microfibers fabricated by blow-spinning, homogeneously Mn and La doped in the LiCoO 2 host and uniformly Li–Ti–O segregated at the LiCoO 2 surface can be realized in every batch of samples. It is demonstrated that the Mn and La codoping can suspend the intrinsic instability and increase the Li + diffusivity of the LiCoO 2 host, and the Ti-based coating can stabilize the interface of LiCoO 2 particles at the charging voltage up to 4.5 V. As a result, the obtained comodified LiCoO 2 cathode shows the best rate performance (1.85 mAh cm –2 at 2C) and longest cycling stability under an areal capacity of 2.04 mAh cm –2 (83% capacity retention over 300 cycles at 0.3C), in comparison to previously reported LiCoO 2 cathodes.