Nickel-rich lithium transition-metal oxides for Li-ion batteries have been interested under intense commercialization as high-energy cathode materials because of their high specific capacity and relatively low cost. However, it still demands the necessities of higher energy density and more improved thermal stability to compete with requirements of smart mobile applications and x-EVs (extended electric vehicles). Accordingly, further research to increase both Ni content over 60 mol% and the cut off voltage to more than 4.5 V are being carried out to increase the energy density of Li-ion cells. However, two critical problems (structural instability both at >60 °C cycling and fast exothermic oxygen evolution at >200 °C) affecting such Ni contents should be solved. Here, we present electrochemical performance of a nickel-rich lithium transition-metal oxide (Ni content from 60 mol% to 91 mol %. Furthermore, by employing various surface chemistry on the cathode materials such as dry powder mixing, direct precipitation, colloidal deposition, Improvement of structural instability have been studied. The degradation of LiMO2 (M = Co, Ni, and Mn) cathode materials was strongly related to their surface chemistry. Among the proposed degradation mechanisms, the irreversible formation of inactive di- or tri-valant Ni species, particularly those localized in surface regions, are the products of such reactions. In other words, when the cathode materials are charged above 4.3 V, the cathodes could be partially transformed into an electrochemically inactive NiO-like phase or spinel structure with volumetric changes due to the migration of the Ni cations from the original transition metal (TM) layers. Our surface treatment cathode materials suppressed formation of NiO-like phase or spinel structure over 5% compared with bare cathode materials. The experimental results suggest one of way for applications that require high energy, long maintain life and excellent safety.