Advanced design strategies for enhancing the thermal stability of Ni-rich co-free cathodes towards high-energy power lithium-ion batteries

Abstract

The global market share of electric vehicles has rapidly grown from ∼10 % in 2022 to ∼18 % in 2024. However, safety issue is a crucial obstacle hindering the commercialization of high-energy lithium-ion batteries. The inferior thermal stability exhibited by high-energy Ni-rich cathodes has severely affected their practical application in LIBs. Particularly, Co in Ni-rich cathodes promotes lattice oxygen release, leading to reduced structural and thermal stability. Therefore, the development of Ni-rich Co-free cathode materials (NRCFs) is promising. Herein, the detrimental effects of Co on the thermal stability of Ni-rich layered oxides are demonstrated. Thereafter, we summarize in detail the popular modification strategies and mechanisms for enhancing the thermal stability of NRCFs. Finally, conclusions and future challenges and prospects for boosting the thermal stability of NRCFs are presented. Notably, synergistic modification strategies combining high-entropy doping and surface coating in single-crystal cathode materials is an efficient approach to significantly improve the thermal stability. Understanding the thermal stability of NRCFs has become urgent for the large-scale application of high-energy LIBs. More effective thermal safety strategies will be aroused to promote the development of next-generation power LIBs. This review aims to inspire further exploration of safer NRCFs featuring higher reversible capacity, attracting interest from both academic and industrial communities to accelerate the commercialization of NRCFs and promote the sustainable development of high-energy LIBs.