Synthesis and Electrochemical Performance of Nickel-Rich Layered-Structure LiNi_0.65Co_0.08Mn_0.27O₂Cathode Materials Comprising Particles with Ni and Mn Full Concentration Gradients (original) (raw)

2016, Journal of The Electrochemical Society

Carbon-coated LiMnBO 3 /C is synthesized by a solgel method using polyethylene glycol 6000 (PEG-6000) as carbon source. The influences of different sintering temperatures on the crystal structure, morphology, and electrochemical performance of LiMnBO 3 /C composites are investigated. XRD results indicate that the samples consist of the monoclinic phase LiMnBO 3 (m-LiMnBO 3) and the hexagonal phase LiMnBO 3 (h-LiMnBO 3), and the amount of m-LiMnBO 3 is reduced and the h-LiMnBO 3 is increased with the increasing sintering temperature. The particle size of the samples is about 500 nm, and the surface of the particles is coated with a thick amorphous carbon layer. The LiMnBO 3 /C synthesized at 750°C exhibits the initial discharge capacities of 213.4, 170.8, and 109.7 mAh g −1 at 0.025, 0.05, and 0.5 C rates, respectively, and shows better cycling performance than that of bare LiMnBO 3. The enhanced electrochemical performance might be largely attributed to the uniformly coated carbon layers from decomposition of the PEG-6000.