Multishell Precursors Facilitated Synthesis of Concentration-Gradient Nickel-Rich Cathodes for Long-Life and High-Rate Lithium-Ion Batteries.

The rational design of concentration-gradient (CG) structure is demonstrated as an available approach to improve the electrochemical performances of high-energy nickel-rich cathodes for lithium-ion batteries (LIBs). However, the complicated preparing processes, especially the CG-precursors, generally result in the less-than-ideal repeatability and consistency that is regarded as an extreme challenge for the widespread commercialization. Thus, the innovative strategy with facile steps and the feasibility of large-scale preparation for commercialized applications should be urgently developed. Herein, through the temperature-tunable cation diffusion, the feasibility of controllable preparation of nickel-rich CG-LiNi0.7Co0.15Mn0.15O2 (NCM) from multishell precursors is first demonstrated. As expected, the Li/CG-NCM half cells show much enhanced cycle-life, rate property, and safety because of the mitigated side-reactions and fast Li+ kinetics. Besides, the Li4Ti5O12/CG-NCM full cells also exhibit long-term lifespan, 95% capacity retention even after 2000 cycles, and high-rate behaviors. Importantly, by contrast with the conventional techniques that prepare CG cathodes from CG precursors, the proposed new synthesis strategy from multishell precursors is suitable for large-scale preparation. Overall, this multishell precursor-facilitated synthesis probably promotes the practical applications of CG cathodes for state-of-the-art LIBs and also can be easily expanded to controllably preparing spinel- and olive-type CG cathodes.