Boosting rate performance of LiNi0.8Co0.15Al0.05O2 cathode by simply mixing lithium iron phosphate

• Published in: Journal of alloys and compounds 2020-06, Vol.827, p.154296, Article 154296
• Main Authors: Huang, Wen-Jin, Zheng, Jia-Yu, Liu, Jian-Jun, Yang, Rui-Ming, Cheng, Fei-Xiang, Suo, Hong-Bo, Guo, Hong, Xia, Shu-Biao
• Format: Article
• Language: English
• Subjects: Cathode material; Cathodes; Charge transfer; Electrode materials; Li ion batteries; LiFePO4; LiNi0.8Co0.15Al0.05O2; Lithium; Lithium-ion batteries; Rate performance; Rechargeable batteries; Solid electrolytes
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.154296

LiNi0.8Co0.15Al0.05O2 (NCA), a cathode material for lithium-ion batteries (LIBs), is a promising material due to its high specific capacity. However, there are drawbacks like high cost, safety issues, and limited cycle-performance that represent obstacles for commercial applications. This study describes a simple ballmilling method to modify the surface of NCA materials and fill the gaps between particles by LiFePO4 (LFP) cathode to improve its charge/discharge rate. The results show that NCA@5LFP, mixed with 5 wt % LFP, has the best cycling and rate performance, with a higher capacity-retention (89.4% after 200 cycles, at 2C). Post-electrochemical and in-situ analysis reveal more detailed reasons of the observed improvements. The formation of a more stable solid electrolyte interface film in the NCA@5LFP hybrid electrode helps ensure the orderliness of the NCA structure, by reducing the charge-transfer resistance, and increasing the channel for lithium ion de-intercalation. All these factors help improve the battery performance. •Improved charge/discharge rate via NCA@LFP mixed electrode by simple ball-milling.•In-situ XRD reveals evolution of NCA@5LFP electrode structure.•Post-electrochemical TEM and XPS reveal interface structure and element distribution.