Surface-Modified Lithium Cobalt Oxide (LiCoO₂) with Enhanced Performance at Higher Rates through Li-Vacancy Ordering in the Monoclinic Phase

Abstract

Lithium cobalt oxide (LCO) is yet a preferred choice because of its unique structure and electrochemical relationship. However, LCO sacrifices its structural stability and associated battery safety at higher voltage and a high rate of operation in current battery technology. To mitigate such problems, a targeted strategy has been adopted with a thin lithium cobalt manganese oxide (LiCo0.5Mn1.5O4, LCMO) coating on the LCO cathode by easy and inexpensive microwave-assisted synthesis. The as-prepared cathode structure showed a tiny amount of manganese­(III) ion (Mn3+) diffusion into the bulk of LCO, which resulted in the increase of its lattice parameter and favoring the Li-ion diffusion in LCO cathode and enables a faster cycling rate 3C (20 min charging–discharging) for longer periods of time. The structural entropy estimation has been utilized to evaluate the arrangement of Li ions and the vacancy in the LCO lattice at different states of charge to investigate the stability of coated LCO at higher voltage. A comprehensive study at higher rate capability at 3C, 5C (12 min), and even at 10C (6 min) current rates and stability at a higher cutoff voltage for modified LCO has been reported here. Finally, the current study is ended with full-cell fabrication with silicon-carbon anodes and LCMO-coated-LCO cathodes in two-layer pouch-type cell format (∼15 mAh capacity) and displayed a commercial feasibility.

High-Speed and One-Step Deposition of a LiCoO2 Thin-Film Electrode by a High-Repetition 1064 nm Nd:YAG Fiber Laser

“…The Co 3 O 4 phase disappeared at 350–450 °C and reappeared at 550 °C due to insufficient oxygen pressure. In fact, the coexisting of HT-LCO with Co 3 O 4 was widely reported. ,, …”

“…It should be noticed that temperatures higher than 550 °C are beneficial for LiCoO 2 itself, as reported by tremendous literature. 23,36,47,48 24,49,50 The phase transition, starting at ∼300 °C, was captured by the optical microscope during Raman characterization. In Figure 4(a), two phases coexist forming a blue matrix and dark discs.…”

“…The Co 3 O 4 phase disappeared at 350−450 °C and reappeared at 550 °C due to insufficient oxygen pressure. In fact, the coexisting of HT-LCO with Co 3 O 4 was widely reported 24,49,50. The phase transition, starting at ∼300 °C, was captured by the optical microscope during Raman characterization.…”

Effects of Ru doping on the structural stability and electrochemical properties of Li2MoO3 cathode materials for Li-ion batteries

“…1 As a widely used energy storage and conversion device, the energy density of a lithium-ion battery is mainly limited by the cathode material. 2,3 The capacity of conventional cathode materials, such as the layered material LiCoO 2 , 4,5 olivine-type material LiFePO 4 , 6,7 and spinel-type material LiNi 0.5 Mn 1.5 O 4 , 8,9 is usually less than 200 mA h g −1 , which makes it difficult to meet the energy density demand of next-generation rechargeable batteries. The cathode material x Li 2 MnO 3 ·(1− x )LiMO x (0 < x < 1) with rich Li ions and a layered structure has attracted extensive attention due to its high reversible specific capacity of 250 mA h g −1 and high working voltage (>3.5 V vs. Li + /Li).…”

Synergistic Effect of Bis(2,2,2-trifluoroethyl) Carbonate and Succinonitrile in Suppressing the Dissolution of Nickel for Performance Improvement of Nickel-Rich Lithium Metal Batteries

“…Many efforts have been undertaken to improve the stability and safety of high-energy LIBs, including cathode modification, anode prelithiation, electrode interface passivation, and electrolyte synergistic optimization. − Although high-capacity cathode and anode materials have been well developed and commercialized, there is still a rare major breakthrough in the electrolyte area . The strategies of electrolyte synergistic optimization have been focused on high concentration, fluorination, and additives targeting the formation of the stable electrode/electrolyte interface or eliminating the residual acid and trace water in electrolytes. − These methods were demonstrated to be effective in improving the stability of high-energy LIBs at the initial cycle process.…”