Research Progress on Coating and Doping Modification of Nickel Rich Ternary Cathode Materials

doi:10.15541/jim20190568

Abstract

Abstract:

In recent years, the development of new energy vehicles industry is accelerating. Lithium nickel cobalt manganese/aluminum oxide ternary cathode materials (NCM/NCA), especially with the nickel content ≥50%, has aroused great interest in both academia and industry. This is mainly due to the fact that the aggregative parameters of performance and cost of NCM/NCA are superior to those of traditional cathode materials, such as LiCoO₂ and LiFePO₄. However, the application of NCM/NCA is affected by a number of drawbacks, including poor safety and insufficient cycle stability and so on, which are mainly attributed to its crystal and surface structure. Researchers have carried out various efforts to solve these problems and further improve the performance of NCM/NCA. Some remarkable results have been achieved in the past few years. In this review, the latest research progress on coating and doping of Ni-rich ternary cathode materials is summarized from the view on the mechanism of structural and electrochemical improvement of NCM/NCA. Finally, the perspective for the development of NCM/NCA cathode materials is also prospected.

Key words: lithium nickel cobalt manganese oxide, coating, doping, mechanism

CLC Number:

O646

BAI Xiangtao,BAN Liqing,ZHUANG Weidong. Research Progress on Coating and Doping Modification of Nickel Rich Ternary Cathode Materials[J]. Journal of Inorganic Materials, 2020, 35(9): 972-986.

Figures/Tables 11

Fig. 1 Mass spectroscopy profiles for the oxygen (O2, m/z=32) collected simultaneously during measurement of TR-XRD (upper panel) and the corresponding temperature region of the phase transitions for NCM (lower panel) [19]

Fig. 2 Degradation mechanisms of NCM523 and phase transformation after cycle tests under high-voltage conditions[20]

Fig. 3 5th discharge profiles of pristine and coated NCM523 (3.0~4.6 V)[49] (a) 1C; (b) 3C; (c) 6C

Table 1 Discharge capacities of Li-ion batteries with different coating amounts[52]

Sample	Discharge capacity /(mAh·g^-1)
Sample	0.1C /3 cycles	1C /5 cycles	2C /5 cycles	5C /5 cycles	10C /5 cycles	0.1C /5 cycles*
0	196.8	168.9	155.8	131.8	94.5	184.6
1wt%	213.9	185.5	170.2	148.1	121.6	207.2
2wt%	203.8	161.1	147.9	122.6	92.1	195.7

Fig. 4 Schematic illustration of byproducts on the surfaces of (a) bare and (b) lithium phosphate-coated NCM622 after cycling 150 times[53]

Fig. 5 (a-d) SEM images of the cathode cracks in the particles cycled 100 times (4.7 V), and (e) schematic diagram showing crack formation[81]

Fig. 6 Typical cycling performance of undoped and Mo-doped NCM523 at (a) 45 ℃ (4.3, 4.4, 4.5, and 4.6 V, C/3 rate) and (b) 30 ℃ (2.8-4.3 V, different rates)[96]

Fig. 7 Suggested mechanism for Ni2+ migration leading to a partial spinel nucleus[104] Red: oxygen atoms; Grey: Ni atoms; Violet: Mn atoms; Blue: cobalt atoms

Table 2 Cycling performances and rate capabilities of NCM622 with different doping agents[104]

Sample	Cycling performance (1C@200*)		Rate performance
Sample	3.0-4.4 V	3.0-4.6 V	16C/0.5C
Pristine	75.59%	72.99%	64.94%
Zr	87.61%	81.05%	73.94%
Zr/Ti	94.20%	91.71%	79.57%

Fig. 8 (a) Cycling performance and (b) DSC results of different cathodes[115]

Fig. 9 Schematic illustration of the disordered layered phase coating layer[133]

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