Formation and Effect of Residual Lithium Compounds on Li-Rich Cathode Material Li_1.35[Ni_0.35Mn_0.65]O₂

Abstract

Li-rich cathode materials are regarded as ideal cathode materials, owing to their excellent electrochemical capacity. However, residual lithium compounds, which are formed on the surface of the materials by reacting with moisture and carbon dioxide in ambient atmosphere, can impair the surface structure, injure the capacity, and impede the electrode fabrication using Li-rich materials. Exposure to air atmosphere causes the formation of residual lithium compounds; the formation of such compounds is believed to be related to humidity, temperature, and time during handling and storage. In this study, we demonstrated for the first time an artificial strategy for controlling time, temperature, and humidity to accelerate exposure. The formation and effect of residual lithium compounds on Li-rich cathode material Li 1.35 [Ni 0.35 Mn 0.65 ]O 2 were systematically investigated. The residual lithium compounds formed possessed primarily an amorphous structure and were partially coated on the surface. These compounds include LiOH, Li 2 O, and Li 2 CO 3 . Li 2 CO 3 is the major component in residual lithium compounds. The presence of residual lithium compounds on the material surface led to a high discharge capacity loss and large discharge voltage fading. Understanding the formation and suppressing the effect of residual lithium compounds will help prevent their unfavorable effects and improve the electrochemical performance.

Boosting Cell Performance of LiNi0.8Co0.15Al0.05O2 via Surface Structure Design

“…Presently, electric vehicle technology advances require high energy density from Li‐ion batteries for commercial realization. Ni‐rich materials have attracted much attention as potential candidates due to their high reversible capacity, discharge working voltage, and relatively low costs . However as Ni content increases in Ni‐rich electrodes, they begin to exhibit poor Li storage characteristics and rapid degradation due to residual Li and structural instability .…”

Fabrication of SiOx-G/PAA-PANi/Graphene Composite With Special Cross-Doped Conductive Hydrogels as Anode Materials for Lithium Ion Batteries

“…Yet the current graphite anode with an unsatisfactory specific capacity of ∼372 mA h g −1 (LiC 6 ) can ′ t follow the development of modern equipment for high energy storage system (Casimir et al, 2016;Zuo et al, 2017;Han et al, 2018;Yi et al, 2018Yi et al, , 2019Zheng et al, 2018Zheng et al, , 2020Xiao et al, 2019). Hence, silicon has become a potential candidate to replace commercial graphite anode for LIBs in that it has higher capacity (∼4,200 mA h g −1 ), suitable discharge platform (∼0.4 V vs. Li/Li + ) and sufficient resources (Casimir et al, 2016;Jiang et al, 2016;Xu et al, 2018;An et al, 2019;Liu Y. et al, 2019a;Yang et al, 2019;Zhou et al, 2019;Zuo et al, 2019). Nevertheless, the two stubborn disadvantages of silicon, including the deterioration of electrode structure integrity as a result of gradual enhancement of pulverization happening in the repetition of discharge/charge process, as well as poor conductivity, have been the main obstacles to its application (Zhao et al, 2016;Zuo et al, 2017).…”

Surface homogenizing heterostructure coatings induced by Ti 3 C 2 T x MXene for enhanced cycle performance of lithium‐rich cathode materials

“…However, a large number of researches show that many problems of lithium‐rich materials still need to be solved. For example, large initial irreversible capacity (ICR) loss, poor rate performance, and terrible cycle stability . One of the most critical and difficult problems to solve is that the lithium‐rich material is facing a continuous capacity reduction and voltage decay during the cycle, which not only reduces the specific energy, but also the normal operation of the battery management system .…”

“…For example, large initial irreversible capacity (ICR) loss, poor rate performance, and terrible cycle stability. 5 One of the most critical and difficult problems to solve is that the lithium-rich material is facing a continuous capacity reduction and voltage decay during the cycle, which not only reduces the specific energy, but also the normal operation of the battery management system. 6,7 Without doubt, these series of problems are closely related to the structural characteristics of lithium-rich materials.…”