Fig. 1

development history of LIBs cathode materials"

Fig. 2

(a)-(c) Li[Ni x Co y Mn1-x-y ]O2 (x=0.6, 0.8, 0.9, 0.95, 1) cathodes: Initial charge-discharge profiles, cycling performance and variations of c-axis lattice parameters with cell voltage[17]; (d) Schematic diagram of structural degradation of NCM materials after cycling[18]; (e) Magnified cross-sectional SEM images of the first charged state of the NC90, NCM90, and NM90 cathodes[19]"

Fig. 3

(a) The relationship between discharge capacity, and thermal stability and capacity retention; (b) Effects of ternary cathode material properties on electric vehicles life[24]"

Fig. 4

(a) Comparison of cross-sectional SEM images of the NCA cathodes with different Ni contents[20]; (b) Schematic diagram of microcracks in NCM cathodes with different Ni contents[17]"

Fig. 5

(a) Surface side reactions of Ni-rich ternary cathode materials[38]; (b) The microstructure and composition of the solid-electrolyte interface at the surface of Ni-rich cathode materials[43]"

Fig. 6

(a) Schematic illustration of phase transition in the charged NCM cathode materials; (b) Mass spectroscopy profiles for the oxygen collected simultaneously during measurement of TR-XRD and the corresponding temperature region of the phase transitions for NCM[32]"

Fig. 7

(a) Schematic diagram of Li3PO4 and PPy-coated NCM; (b) TEM images of NCM coated with Li3PO4 and PPy[69]; (c) Mechanism of PEDOT coating and oxide coating for NCM[70]"

Fig. 8

(a) Schematic illustration of the effect of boron-doping on the NCM90 cathode's mechanical stability during cycling[87]; (b)-(c) STEM image of a cross-sectional cathode particle and cycling performance of NCM90, NCB90, NCA90, NCW90 and NCTa90 cathodes[88]"

Fig. 9

(a) Schematic illustration of particle fracture in polycrystalline and single-crystal NCM materials[100]; SEM images of sintered SC-NCM; (b) Cross-sectional SEM images of single crystal and polycrystal NCM before and after 600 cycles; (c) Schematic illustration of crack evolution and the internal morphological difference for polycrystalline and single-crystal NCM cathodes during prolong cycling; (d) Cycling performance of polycrystalline and single-crystal NCM cathodes a coin-cell[103]"

Fig. 10

(a)-(b) Schematic diagram and SEM of positive-electrode particle with Ni-rich core surrounded by concentration-gradient outer layer[109]; (c) Schematic description of discharge and charge state: CC90 and CSG90 cathodes showing the internal morphological difference and the sustained damage[111]"

Fig. 11

Combinations of modification strategies for high-nickel ternary cathode materials"