Novel concentration gradient LiNi0.815Co0.15Al0.035O2 microspheres as cathode material for lithium ion batteries

• Published in: Ceramics international 2019-10, Vol.45 (15), p.19420-19428
• Main Authors: Hou, Aolin, Liu, Yanxia, Ma, Libin, Zhang, Ling, Li, Jingjing, Zhang, Pengfei, Chai, Fengtao, Ren, Baozeng
• Format: Article
• Language: English
• Subjects: Concentration-gradient; Hydrothermal method; Li-ion batteries; Microsphere; Ni-rich cathode material
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2019.06.196

A novel concentration gradient LiNi0.815Co0.15Al0.035O2 microsphere is synthesized successfully based on hydrothermal method combined with solid-state sintering process. Compared with traditional coprecipitation method, the prepared microspheres are only about 6 μm in diameter, which is beneficial to shorten the paths of ion/electron diffusion. As demonstrated by cyclic voltammetry (CV) and galvanostatic intermittent titration technique (GITT) tests, the positive electrodes show a remarkable ion diffusion kinetics, which resulted in a superb rate capability. Besides, highly agglomerated primary particles and concentration gradient distribution of element can promote the structure stability of the material, which is beneficial to its cycle performance. As the cathode material, it possesses a capacity up to 196.2 mAh g−1 at 0.1 C with capacity retention of 93% circulated for 100 times at 1 C and capacity retention of 88% circulated for 330 times at 2 C. What's more, a high capacity up to 165.6 mAh g-1 could be achieved even at 5 C. In addition, a reusable lithium-ion full cell is assembled with cathode LiNi0.815Co0.15Al0.035O2 and anode graphite to explore its potential for practical application and it's found to deliver an excellent electrochemical property. This research provides a possible and feasible reference strategy to accelerate the application of Ni-rich cathodes.