These results indicate that sol-gel processing is a promising method for preparing Ni-rich cathode materials. The sample prepared under the optimal conditions had a well ordered hexagonal layered structure. The charge–discharge tests showed that the initial capacities of the sample were and mAhg -1 at the discharge rate of C between and V, respectively. The capacity retention ratio was % at 1 C after 50 cycles. | Vietnam Journal of Chemistry, International Edition, 54(6): 760-764, 2016 DOI: Synthesis, structural and electrochemical properties of Ni-rich material prepared by a sol-gel method Mai Thanh Tung*, Vu Duc Luong Department of Electrochemistry and Corrosion Protection, School of Chemical Engineering Hanoi University of Science and Technology, Hanoi, Vietnam Received 26 July 2016; Accepted for publication 19 December 2016 Abstract We report on a novel synthetic method of sol-gel processing to prepare Ni-rich cathode materials. We also studied and reported on the electrochemical properties of the resultant products. XRD revealed that a single phase Ni-rich powder can be synthesized by sol-gel processing. The Ni-rich material obtained has a high electrochemical capacity and good cycle ability. These results indicate that sol-gel processing is a promising method for preparing Ni-rich cathode materials. The sample prepared under the optimal conditions had a well ordered hexagonal layered structure. The charge–discharge tests showed that the initial capacities of the sample were and mAhg-1at the discharge rate of C between and V, respectively. The capacity retention ratio was % at 1 C after 50 cycles. Keywords. Lithium-ion battery, cathode material, , sol-gel. 1. INTRODUCTION Lithium cobalt oxide (LiCoO2), initially introduced in 1980, has been one of the most widely used positive electrode material in commercial lithium-ion batteries due to its high working voltage, reasonable cycle-life (300-500 cycles), and its easy preparation [1-3]. However, its high cost, toxicity, and the thermal instability of LixCoO2 phases limit its further use in newly developed multifunctional portable devices and electric vehicle systems [4]. LiNiO2 is one of the most attractive nextgeneration cathode-material candidates for lithiumion batteries (LIBs) because its reversible capacity is higher and its cost is