A three-in-one engineering strategy to achieve LiNi0.8Co0.1Mn0.1O2 cathodes with enhanced high-voltage cycle stability and high-rate capacities towards lithium storage

• Published in: Journal of power sources 2022-03, Vol.524, p.231035, Article 231035
• Main Authors: Zhao, Fei, Li, Xiaoying, Yan, Yunsheng, Su, Maoshui, Liang, Longwei, Nie, Ping, Hou, Linrui, Chang, Liming, Yuan, Changzhou
• Format: Article
• Language: English
• Subjects: Full concentration gradient; LiNbO3 coating; LiNi0.8Co0.1Mn0.1O2 cathode; Lithium-ion batteries; Nb gradient doping
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2022.231035

Recently, the Ni-rich layered LiNi0.8Co0.1Mn0.1O2 (NCM811) is established as a promising cathode material for next-generation lithium-ion batteries (LIBs). However, it always suffers from severe bulk structural and interfacial degradation during electrochemical operation. To well address the issues, herein, a three-in-one engineering strategy is devised to construct a stable Nb-doped full concentration-gradient NCM811 coated with rhombohedral LiNbO3 (denoted as N-FCG-NCM811@LNO). In the strategy, each secondary particle possesses a Ni-rich core and a Co/Mn-rich outer surface, along with the Li+-conductive LNO coating layer and surface gradient Nb doping. It is the synergistic contributions from three-aspect design (i.e., FCG construction, surface coating and heteroatom doping) that renders NCM811 cathodes with stable crystalline structure and surface, mitigated microcracks, accelerated Li+ diffusion kinetic, and suppressed interfacial phase transition over cycling. The optimum N-FCG-NCM811@LNO achieves the improved capacity retention at high cut-off voltages (∼85.1% after 300 cycles between 3.0 and 4.4 V, and ∼80.5% after 200 cycles between 3.0 and 4.5 V both at 1C rate) and better high-rate capability (∼162.4 mAh g−1 at 10C). More meaningfully, the instructive electrode design concept here can be extended to other Ni-rich cathodes for high-energy/power LIBs via the simple yet scalable fabrication process. •A three-in-one engineering strategy is devised to construct N-FCG-NCM811@LNO.•The FCG design accommodates anisotropic internal strain and ensures bulk stability.•LNO coating favors Li + diffusion kinetic and minimizes surf-/interfacial decay.•Nb doping reduces cation mixing degree/phase transitions and microcracks in cycles.•The optimum cathode achieves superb high-rate capability and capacity retention.