Enhancing the Structure and Interface Stability of LiNi0.83Co0.12Mn0.05O2 Cathode Material for Li-Ion Batteries via Facile CeP2O7 Coating

High-energy Ni-rich layered cathode materials (LiNixCoyMn1–x–yO2, x ≥ 0.8) for lithium-ion batteries (LIBs) suffer greatly from cation disorder and poor thermal, structure, and interface stability, causing an unsatisfactory cycle and safety performance. Herein, cerium pyrophosphate (CeP2O7, abbreviated as CPPO) was coated on the secondary particle surface of LiNi0.83Co0.12Mn0.05O2 via a facile PEG assisted aqueous deposition method. Compared with the bare material, lower cation disorder occurs in the modified sample due to lower Ni2+ content. A well-ordered CPPO crystalline coating layer could be observed on the particle surface. Suppressed structural deterioration due to more stable interface properties leads to better rate capability. Also, better thermal stability has been achieved after the surface treatment. The modified sample maintains 92.38% of the initial capacity after 100 cycles at a 2C rate and upper cutoff voltage of 4.3 V. After cycling for 200 cycles at a 1C rate and higher cutoff voltage of 4.4 V, 80.54% of the initial capacity is maintained. In addition, the discharge capacity under a higher rate is greatly improved under the upper cutoff voltage of 4.3/4.5 V.