Vacancy-engineered LiMn<sub>2</sub>O<sub>4</sub> embedded in dual-heteroatom-doped carbon via metal-organic framework-mediated synthesis towards longevous lithium ion battery
Xiaoming Lin, Jia Lin, Xiaomeng Lü, Xiaohong Tan, Hao Li, Wanxin Mai, Yuhong Luo, Yongbo Wu, Shuangqiang Chen, Chao Yang, Yong Wang
Abstract
Abstract Spinel LiMn 2 O 4 (LMO) is deemed to be a promising cathode material for commercial lithium-ion batteries (LIBs) in prospect of its cost-effectiveness, nontoxicity, fabulous rate capability, and high energy density. Nevertheless, the LMO is inevitably confronted with sluggish diffusion kinetics and drastic capacity degradation triggered by multiple issues, including Jahn–Teller distortion, Mn dissolution, and structural attenuation. Thereinto, a metal-organic framework (MOF) chemistry engineering for hierarchical micro-/nano-structural F, O-dual-doped carbon embedded oxygen vacancy enriched LiMn 2 O 4 cathode (O V -LMO@FOC) is proposed for longevous LIBs. Bestowed by experimental and theoretical implementations, systematic investigations of O V -LMO@FOC endow that the meticulous integration of F, O-dual-doped carbon and oxygen vacancy in LMO-based cathode reconfigures the electronic structure, boosts electronic conductivity, expedites diffusion capability, facilitates energetically preferable Li + adsorption, and suppresses Mn dissolution in the electrolyte, consequently achieving fabulous long-term cycling stability. As expected, the O V -LMO@FOC behaves with compelling electrochemical performance with prosperous reversible capacity (130.2 mAh g −1 at 0.2 C upon 200 cycles), exceptional rate capacity (93.7 mAh g −1 even at 20 C), and pronounced long-term cyclability (112.5 mAh g −1 after 1200 cycles with 77.6% capacity retention at 1 C). Even at the ultrahigh current density of 5 C, the O V -LMO@FOC bears a brilliant capacity of 96.9 mAh g −1 upon 1000 cycles with an extraordinary capacity retention of 90.7%, and maintains a discharge capacity of 70.9 mAh g −1 upon 4000 cycles. This work envisions the MOF-chemistry in surface modification and electronic modulation engineering of high-performance cathode materials towards industrialization in automotive market.