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

Abstract

Lithium-rich manganese-based cathode materials are expected to promote the commercialization of lithium-ion batteries to a new stage by virtue of their ultrahigh specific capacity and energy density advantages. However, they are still restricted by complex phase transitions and electrochemical performance degradation caused by labile anion charge compensation. A deep understanding of the electrochemical properties contained in their intrinsic structures and the key driving factors of structural deterioration during cycling are crucial to guide the preparation and optimization of lithium-rich materials. Considering recent progress, this review introduces the intrinsic properties of Li-rich manganese-based cathode materials from interatomic interactions to particle morphology at multiple scales in the spatial dimension. The charge compensation mechanism and energy band reorganization of the initial charge and discharge, the structural evolution during cycling and the electrochemical reaction kinetics of the materials are analyzed in the temporal dimension. Based on the relationship between structure and electrochemical performance, preparation methods and modification methods are introduced to guide and design cathode materials. Effective characterization methods for studying anion charge compensation behavior are also demonstrated. This review provides important guidance and suggestions for making full use of the high specific capacity in these materials derived from anion redox and the maintaining of its stability.

Easy and Scalable Syntheses of Li1.2Ni0.2Mn0.6O2

“…After the phase transition, a disproportionate reaction can occur, producing Mn +4 and Mn +2 . The latter, being soluble in the electrolyte, can dissolve and cause a loss of active material [58]. This leads to fading of the capacity [59], as is mainly observed in the material prepared by SS reaction.…”

Modification Strategies and Challenges of High‐Performance Lithium‐Rich Manganese‐Based Cathode Materials

“…The main difference between layered and disordered lithium‐rich materials lies in the variation of Li + diffusion channels, resulting in different diffusion barriers and lithium diffusivity within the materials. [ 12 ] There is a view that the degree of structural order in oxide materials directly influenced their properties. [ 13 ] However, in 2014, Ceder et al discovered that the disordered halite material Li 1.211 Mo 0.467 Cr 0.3 O 2 exhibited exceptional cycle performance and specific capacity, challenging the previous understanding of the structure–activity relationship.…”

Advances in lithium-ion battery materials for ceramic fuel cells

“…To address these challenges, the doping of polymetallic elements was developed to stabilize the crystal structure, and thus the disadvantage of single doping can be avoided with additional advantages, e.g., enhanced electrical properties. Recently, LiNi x Co y Mn 1-x-y O 2 (NCM) [92] and LiNi x Co y Al 1-x-y O 2 (NCA) have attracted significant attention as new-generation LIB electrodes because of their higher specific capacity and energy density [93] . For example, the optimized composition of LiNi 0.8 Co 0.15 Al 0.05 O 2 has been used in Tesla's electric vehicles with improved cost-effectiveness.…”