Structural Understanding for High‐Voltage Stabilization of Lithium Cobalt Oxide

Abstract

The rapid development of modern consumer electronics is placing higher demands on lithium cobalt oxide (LiCoO2; LCO) cathode that powers them. Increasing operating voltage is exclusively effective in boosting LCO capacity and energy density but is inhibited by the innate high‐voltage instability of LCO structure that serves as the foundation and determinant of its electrochemical behavior in lithium‐ion batteries (LIBs). This has stimulated extensive research on LCO structural stabilization. Here, we focus on the fundamental structural understanding of LCO cathode from long‐term studies. Multi‐scale structures concerning LCO bulk and surface and various structural issues along with their origins and corresponding stabilization strategies with specific mechanisms are uncovered and elucidated at length, which will certainly deepen and advance our knowledge of LCO structure and further its inherent relationship with electrochemical performance. And based on these understandings, remaining questions and opportunities for future stabilization of LCO structure are also emphasized.This article is protected by copyright. All rights reserved

A pre-fatigue training strategy to stabilize LiCoO2 at high voltage

“…Meanwhile, during the charging process from 4.5 to 4.6 V, the loss of electrons on the oxygen ions led to the weakening of the O interlayer repulsion and the contraction of the c-axis spacing, which resulted in the shift of the (003) diffraction peak to a higher angle. 40,41 It is observed that the (003) diffraction peak shift of P-LCO breaks during this process, and the sudden phase transition of the sample from the O3 phase to the H1-3 phase reflects the abrupt change in lattice parameters, thus leading to the disruption of the lamellar structure. In the OAO-LCO sample, there is a similar expansion process along the c-axis when charging to 4.5 V. The expansion process of the OAO-LCO sample is similar along the c-axis.…”

Evolution Path of Precursor-Induced High-Temperature Lithiation Reaction during the Synthesis of Lithium-Rich Cathode Materials

“…To meet the requirements of electric vehicles and large-scale energy storage systems, the development of a higher energy density lithium-ion battery has become very urgent. − With a high theoretical capacity and low cost, Li- and Mn-rich layered transition metal oxides (LMLO), which are a promising class of cathode materials, have drawn intensive attention in recent years. − The coprecipitation route followed by a solid-state reaction has been widely studied as a mainstream fabrication method to achieve high-performance lithium-ion cathode materials. − Although the solid-state reaction is simple in operation, the synthesis route undergoes complex chemical reactions, such as decomposition process, solid phase diffusion, nuclear reaction, and crystal growth, which is unclear and should be studied from the structure of the original materials. − …”

Enhancing the Structural Stability of LiCoO2 at Elevated Voltage via High-Valence Sb Doping

“…Numerous researchers have explored a variety of modification methods to improve the cycling stability of LiCoO 2 at voltages above 4.45 V. − Among these methods, ion doping is recognized as a valuable approach to enhance its cycling lifespan. − For instance, Li et al strengthened the Co–O bonds and suppressed structural phase transitions by introducing Gd into the transition metal layer of LiCoO 2 . The doped LiCoO 2 exhibited a capacity retention of 82.7% after 100 cycles within the voltage range of 3–4.6 V .…”