Preparation\nand Rate Capability of Carbon Coated LiNi_1/3Co_1/3Mn_1/3O₂ as Cathode\nMaterial in Lithium Ion Batteries

Abstract

LiNi_1/3Co_1/3Mn_1/3O₂ (NCM) is regarded\nas a promising material for next-generation lithium\nion batteries due to the high capacity, but its practical applications\nare limited by the poor electronic conductivity. Here, a one-step\nmethod is used to prepare carbon coated LiNi_1/3Co_1/3Mn_1/3O₂ (NCM/C) by applying active carbon as\nreaction matrix. TEM shows LiNi_1/3Co_1/3Mn_1/3O₂ particles are homogeneously coated by carbon\nwith a thickness about 10 nm. NCM/C delivers the discharge capacity\nof 191.2 mAh g^–1 at 0.5 C (85 mA g^–1) with a columbic efficiency of 91.1%. At 40 C (6800 mA g^–1), the discharge capacity of NCM/C is 54.6 mAh g^–1, whereas NCM prepared through sol–gel route only delivers\n13.2 mAh g^–1. After 100 charge and discharge cycles\nat 1 C (170 mA g^–1) the capacity retention is 90.3%\nfor NCM/C, whereas it is only 72.4% for NCM. The superior charge/discharge\nperformance of NCM/C owes much to the carbon coating layer, which\nis not only helpful to increase the electronic conductivity but also\ncontributive to inhibit the side reactions between LiNi_1/3Co_1/3Mn_1/3O₂ and the liquid electrolyte.