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

Abstract

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-LiNiCoMnO (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 LiTiO/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.

Heat Diffusion‐Induced Gradient Energy Level in Multishell Bisulfides for Highly Efficient Photocatalytic Hydrogen Production

“…The thermal diffusion during the solidification process has a significant effect on the chemical composition distribution. [ 25,62,63 ] According to the diffusion formula where D is the diffusion coefficient, D 0 is the frequency factor, Q is the diffusion activation energy, R is the gas constant, and T is the heat treatment temperature. [ 64 ] The heat treatment temperature and the diffusion activation energy substantially determine the value of the diffusion coefficient.…”

Surface/Interface Structure Degradation of Ni‐Rich Layered Oxide Cathodes toward Lithium‐Ion Batteries: Fundamental Mechanisms and Remedying Strategies

“…Another feasible strategy to achieve endurable structure but not sacrifice the capacity of the Ni-rich cathodes is the fine design of chemical concentration gradient structure, which generally includes two different types: surface concentration gradient [130,134,218,220,[342][343][344][345][346][347][348] and full concentration gradient (FCG). [219,221,222,[349][350][351][352][353][354][355][356][357][358] In the concentration gradient structures, the core zones are rich in electrochemical active Ni element, while the Mn/Al elements functioning as improving the structural stability mainly center on the surface region, especially during high-voltage cycling.…”

Multi-dimensional correlation of layered Li-rich Mn-based cathode materials

“…This strong coupling effect makes the rapid redox of Co (3+δ)+ /Co 4+ a medium to improve the kinetics of anion redox in lithium-rich materials [Figure 10H]. Other anions, such as S 2-, exhibit faster reaction kinetics and lower voltage hysteresis than O 2but also lower the redox potential [113] and affect the energy density due to the weaker electronegativity.…”