Hu Xinhong, Du Kai, Zhang Yujia, Hou Yabin, Zhao Huiling, Bai Ying
International Joint Research Laboratory of New Energy Materials and Devices of Henan Province, School of Physics and Electronics, Henan University, Kaifeng 475004, PR China.
International Joint Research Laboratory of New Energy Materials and Devices of Henan Province, School of Physics and Electronics, Henan University, Kaifeng 475004, PR China.
J Colloid Interface Sci. 2023 Jun 15;640:1005-1014. doi: 10.1016/j.jcis.2023.03.032. Epub 2023 Mar 7.
With high specific energy density, Ni-rich layered LiNiCoMnO (NCM) material has become one promising cathode candidate for advanced lithium-ion batteries (LIBs). However, severe capacity fading induced by microstructure degradation and deteriorated interfacial Li transportation upon repeated cycling makes the commercial application of NCM cathode in dilemma. To address these issues, LiAlSiO (LASO), one unique negative thermal expansion (NTE) composite with high ionic conductivity, is utilized as a coating layer to improve the electrochemical performances of NCM material. Various characterizations demonstrate that LASO modification can endow NCM cathode with significantly enhanced long-term cyclability, through reinforcing the reversibility of phase transition and restraining lattice expansion, as well as depressing microcrack generation during repeated delithiation-lithiation processes. The electrochemical results indicate that LASO-modified NCM cathode can deliver an excellent rate capability of 136 mAh g at a high current rate of 10 C (1800 mA g), larger than that of the pristine cathode (118 mAh g), especially higher capacity retention of 85.4% concerning the pristine NCM cathode (65.7%) over 500 cycles under 0.2 C. This work provides a feasible strategy to ameliorate the interfacial Li diffusion and suppress the microstructure degradation of NCM material during long-term cycling, which can effectively promote the practical application of Ni-rich cathode in high-performance LIBs.
富镍层状LiNiCoMnO（NCM）材料具有高比能量密度，已成为先进锂离子电池（LIBs）颇具前景的正极候选材料。然而，在反复循环过程中，由微观结构退化和界面锂传输恶化引起的严重容量衰减使NCM正极的商业应用陷入困境。为了解决这些问题，具有高离子电导率的独特负热膨胀（NTE）复合材料LiAlSiO（LASO）被用作涂层来改善NCM材料的电化学性能。各种表征表明，LASO改性可以通过增强相变的可逆性、抑制晶格膨胀以及抑制反复脱锂-锂化过程中的微裂纹产生，赋予NCM正极显著增强的长期循环稳定性。电化学结果表明，LASO改性的NCM正极在10 C（1800 mA g）的高电流速率下能够提供136 mAh g的优异倍率性能，高于原始正极（118 mAh g），特别是在0.2 C下500次循环后，相对于原始NCM正极（65.7%），其容量保持率更高，达到85.4%。这项工作提供了一种可行的策略，可改善界面锂扩散并抑制NCM材料在长期循环过程中的微观结构退化，这能够有效促进富镍正极在高性能LIBs中的实际应用。
