Demystifying the Lattice Oxygen Redox in Layered Oxide Cathode Materials of Lithium-Ion Batteries

Abstract

The practical application of lithium-ion batteries suffers from low energy density and the struggle to satisfy the ever-growing requirements of the energy-storage Internet. Therefore, developing next-generation electrode materials with high energy density is of the utmost significance. There are high expectations with respect to the development of lattice oxygen redox (LOR)a promising strategy for developing cathode materials as it renders nearly a doubling of the specific capacity. However, challenges have been put forward toward the deep-seated origins of the LOR reaction and if its whole potential could be effectively realized in practical application. In the following Review, the intrinsic science that induces the LOR activity and crystal structure evolution are extensively discussed. Moreover, a variety of characterization techniques for investigating these behaviors are presented. Furthermore, we have highlighted the practical restrictions and outlined the probable approaches of Li-based layered oxide cathodes for improving such materials to meet the practical applications.

Facilitating Reversible Cation Migration and Suppressing O2 Escape for High Performance Li‐Rich Oxide Cathodes

“…[1][2][3][4][5] However, these oxides suffer from a big challenge of voltage decay, which is closely related to the issues of irreversible transition metal (TM) cation migration [6] and lattice oxygen escape. [7,8] It is generally accepted that the voltage fade is primarily rooted in the accumulation of irreversible cation migration. A comprehensive investigation of the Li-rich Mn-based oxide with an exacerbate voltage decline declares that an increasing amount of TM cations are indeed trapped into the Li layers.…”

Advancing to 4.6 V Review and Prospect in Developing High‐Energy‐Density LiCoO2 Cathode for Lithium‐Ion Batteries

“…[76] When the electron are extracted from the overlap region, the ion radius and electrostatic reaction simultaneously reduce, leading to O 2− oxidation, Co dissolution and oxygen loss at high potential. [77,78] Accordingly, continuous O loss during high voltage cycle will result in irreversible phase transitions (CoO 2 →Co 3 O 4 , Figure 5b). [58,79] The generated Co 3 O 4 impedes Li + transport, giving a sharp increase to impedance and capacity decay.…”

Recent Advances in Enhanced Performance of Ni‐Rich Cathode Materials for Li‐Ion Batteries: A Review

“…However, demand for the higher capacity urges to operate the battery at higher potential causes the regulation of lattice oxygen redox to become significant along with the transition metal redox for the realization of enhanced electrochemical performance. [ 58 ] Actually, at a higher positive voltage, there is a significant overlapping of 3d and 2p states of the transition metal and oxygen respectively that makes the oxygen redox active. So, in order to analyze redox activity related to Ni and O, X‐ray absorption spectroscopy, resonant inelastic X‐ray scattering, operando Raman spectroscopy, and operando differential electrochemical mass spectroscopy can be used.…”