A novel core-shell structured nickel-rich layered cathode material for high-energy lithium-ion batteries

Abstract

For enhancing the electrochemical properties of lithium transition-metal oxide, a novel core-shell structured cathode material LiNi0.75Co0.12Mn0.13O2@V2O5 was designed and synthesized. The precursor of the material was made of metal hydroxide in the interior and metal carbonate in the exterior, and with full concentration gradient structure. In this cathode material, the core was the high-Ni material, and the shell was the high-Mn material. The sphere material was coated and penetrated by V2O5 due to the existence of pores. Furthermore, the material was also doped by vanadium element. These were investigated and confirmed by X-ray diffraction, Focused Ion beam, EDS, TEM, etc. The 3 wt% V2O5-coated sample exhibited a remarkable cycling performance, with capacity retention of 86.5% at the current rate of 1 C after 100 cycles. Besides, the rate capability of the V2O5-coated sample was obviously enhanced at high rates (2, 5 and 10 C). The interfacial charge transfer resistance of the material after cycling was obviously decreased by V2O5 coating. The cyclic voltammetry analysis showed that the interfacial polarization of the material was inhibited due to V2O5 coating.