Nickel-rich LiNi0.8Co0.1Mn0.1O2 (LNCM811) is a promising lithium-ion battery cathode material, whereas the surface-sensitive issues (i.e., side reaction and oxygen loss) occurring on LNCM811 particles significantly degrade their electrochemical capacity retentions. A uniform Li2ZrO3 coating layer can effectively mitigate the problem by preventing these issues. Instead of the normally used weak hydrogen-bonding interaction, we present a covalent interfacial engineering for the uniform Li2ZrO3 coating on LiNi0.8Co0.1Mn0.1O2 materials. Results indicate that the strong covalent interactions between citric acid and Ni0.8Co0.1Mn0.1(OH)2 precursor effectively promote the adsorption of ZrO2 coating species on Ni0.8Co0.1Mn0.1(OH)2 precursor, which is eventually converted to uniform Li2ZrO3 coating layers of about 7 nm after thermal annealing. The uniform Li2ZrO3 coating endows LNCM811 cathode materials with an exceptionally high capacity retention of 98.7% after 300 cycles at 1 C. This work shows the great potential of covalent interfacial engineering for improving the electrochemical cycling capability of Ni-rich lithium-ion battery cathode materials.