《Restraining Lattice Oxygen Escape by Bioinspired Antioxidant Enables Thermal Runaway Prevention in Ni−rich Cathode based Lithium−ion Batteries》

Ni−rich cathodes are hopeful materials for advanced lithium−ion batteries (LIBs) due to high capacity. Nonetheless, the chemical crosstalk triggered by reactive oxygen (O*) at elevated temperatures represents a critical factor in thermal runaway (TR). Currently, there are few effective means to prevent this parasitic reaction. Here, inspired by the O* scavenging effect of β−carotene in living organisms, we have innovatively identified that β−carotene can impede TR by restraining the escape of O* during the thermal decomposition of nickel−rich cathodes. Using NCM65 as model and extending to higher nickel content cathodes (NCM811, NCM90), we demonstrate that β−carotene can undergo an in−situ oxygen copolymerization reaction to trapping O*, thereby attenuating chemical crosstalk reactions. Additionally, the generated oxygen copolymer can also adjust band center of the O 2p orbitals of delithiated cathode, alleviating the charge compensation behavior of oxygen anions, and thus delaying the phase transition of charged LiNi0.8Co0.1Mn0.1O2. As a result, the TR trigger temperature of NCM811∣Graphite pouch cell is increased from 131.0 °C to 195.0 °C and maximum temperature is reduced from 657.8 °C to 412.4 °C. This work introduces a new and simple strategy for designing functional additives to block TR, offering a promising avenue for advancing the safety of LIBs.

https://onlinelibrary.wiley.com/doi/10.1002/aenm.202401037