Hard X-ray Photoelectron Spectroscopy Analysis of Surface Chemistry of Spray Pyrolyzed LiNi_0.5Co_0.2Mn_0.3O₂ Positive Electrode Coated with Lithium Boron Oxide

Abstract

It is known that the deterioration of LiNi 0.5 Co 0.2 Mn 0.3 O 2 is suppressed by inhibiting direct contact between the cathodes and the electrolyte by surface coating. In order to evaluate the influence of the electrode/electrolyte interface degradation, it is necessary to eliminate the influence of particle cracking. In this study, LiNi 0.5 Co 0.2-Mn 0.3 O 2 particles with a small size (500 nm to 1 µm) without crack formation after charge-discharge cycling were synthesized by a spray pyrolysis method. Hard X-ray photoelectron spectroscopy was used to investigate the structural changes of the cathode. It was revealed that the cathode coated with lithium boron oxide (LBO) by an antisolvent precipitation method had high durability against the surface structure changes by the reduction of transition metal ions. The formation and dissolution of NiO occurred in the uncoated sample during cycling, but the formation of NiO was suppressed in the LBO-coated sample. It was considered that the structural changes of the active material surface during cycling led to an increase in surface resistance of the uncoated sample, which is the main reason for the capacity fading of the spray pyrolyzed LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode particles.

Recent progress in synthesis and surface modification of nickel-rich layered oxide cathode materials for lithium-ion batteries

“…Therefore, lithium-ion conductors have been developed as alternative coating materials. Hashigami et al prepared lithium boron oxide (LBO)-coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 by an antisolvent precipitation method [186]. XRD results indicated that the diffraction peak intensity ratio of the (003) to the (104) decreased by the coating of LBO.…”

Review—Revealing the Intercrystalline Cracking Mechanism of NCM and Some Regulating Strategies

“…31,[36][37][38][39][40][41] And during high-pressure operation and long-term cycling, intercrystalline cracks can easily diffuse to the particle surface, leading to structural collapse and cycle degradation. [42][43][44][45][46][47] In that case, a series of problems, such as the irreversible phase transition, the side reaction on interface, and the heterogeneity of secondary particles may appear on the crystal surface of NCM cathode when there are still intercrystalline microcracks on the crystal surface of NCM, especially after the nickel content exceeding 60%. 48,49 Moreover, residual lithium compounds (e.g., LiOH, LiHCO 3 and Li 2 CO 3 ) may be formed on the cathode surface in the cycling process of nickel-rich layer.…”

Investigation of Water-Washing Effect on Electrochemical Properties of Ni-Rich NCA Cathode Material for Lithium-Ion Batteries

“…[5][6][7][8] Many strategies have been proposed already to improve these degradation factors for the capacity fading of Ni-rich cathode materials. For example, it was widely reported that surface treatments with various coating materials, such as ZrO 2 , Li 2 WO 4 , LiBO 2 , and Li 2 SiO 3 etc., [9][10][11][12][13][14] give an excellent effect in suppressing the decomposition of electrolyte on the surface of cathode active materials and the inactivation of the surface structure by preventing direct contact between the electrolyte and the cathode active materials. Moreover, Han et al reported that NCM721 (LiNi 0.7 Co 0.2 Mn 0.1 O 2 ) within which B 2 O 3 was incorporated showed the improved cyclabilities by suppressing the crack propagation on high voltage.…”