Ultrahigh\nCapacity Retention of a Li₂ZrO₃‑Coated\nNi-Rich LiNi_0.8Co_0.1Mn_0.1O₂ Cathode Material through\nCovalent Interfacial Engineering

Abstract

Nickel-rich\nLiNi_0.8Co_0.1Mn_0.1O₂ (LNCM811)\nis a promising lithium-ion battery cathode material,\nwhereas the surface-sensitive issues (i.e., side reaction and oxygen\nloss) occurring on LNCM811 particles significantly degrade their electrochemical\ncapacity retentions. A Li₂ZrO₃ coating layer\ncan mitigate the problem by preventing these interfacial issues. However,\nthe capacity retentions still need improvement. The normally used\nsol–gel coating method relies on weak hydrogen-bonding interaction\nbetween coating species (i.e., hydrated ZrO₂) and cathode\nparticles that discourages effective coating layers. Herein, we present\na covalent interfacial engineering for the uniform Li₂ZrO₃ coating on LNCM811 materials. Experiments and density functional\ntheory calculations indicate that the strong covalent interactions\nbetween citric acid and the Ni_0.8Co_0.1Mn_0.1(OH)₂ (NCM811) precursor effectively promote\nthe adsorption of ZrO₂ coating species on the NCM811 precursor,\nwhich is eventually converted to uniform Li₂ZrO₃ coating layers of about 7 nm after thermal annealing. The uniform\nLi₂ZrO₃ coating endows LNCM811 cathode materials\nwith an exceptionally high capacity retention of 98.7% after 300 cycles\nat 1 C. This work shows the great potential of covalent interfacial\nengineering for improving the electrochemical cycling capability of\nNi-rich lithium-ion battery cathode materials.