LI Yanbing ¹, SHAO Weiquan ^1,2, WANG Jianjian ¹, CHEN Sha'ou ^1,2, LI Hongliang ³, WANG Zhen ¹, SUN Jianfa ¹, LI Hui ¹, WU Hao ¹, ZOU Shun ¹

(1.College of Physics Science, Qingdao University, Qingdao, Shandong 266071, China; 2. Key Laboratory of Photonics Materials and Technology, Universities of Shandong, Qingdao, Shandong 266071, China; 3. Cultivating Base for State Key Laboratory of Fiber Materials and Modern Textile, Qingdao University, Qingdao 266071, Shandong, China)

Abstract: 4.7V LiNi_0.5Mn_1.5O₄ cathode material with cubic spinel structure was prepared by oxalate co-precipitation process using LiCl, NiCl₂·6H₂O and MnCl₂·4H₂O as raw materials, oxalate as a precipitant, polyacrylic acid (PAA) as a dispersant agent. The synthesized materials were analyzed and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that all of the samples had cubic spinel structure without any undesired impurities. According to the SEM, the powder had uniform particle size and its aggregation was reduced because of the assistance of polyacrylic acid. The electrochemical performance tests found that all the samplessynthesized by polymer- assisted method possess good capacity retention and rate performance, compared to the sample without PAA addition. The discharge capacity for 3wt% sample was signifi cantly enhanced about 87.5% at 1C, 39.4% at 2C, 43.5% at 5C and 1.5% at 10C with respect to the sample without PAA. The great enhancement could be attributed to an effectively shortened Li-ion diffusion path way.

Key words: lithium battery cathode material; LiNi_0.5Mn_1.5O₄; polyacrylic acid; co-precipitation