Negative Thermal Expansion Material: Promising for Improving Electrochemical Performance and Safety of Lithium-Ion...

Heat and deformation are responsible for poor performance and safety of batteries, but they cannot always be avoided. To address these two issues, ZrW₂O₈, a negative thermal expansion (NTE) material, was adopted to modify LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) to decline deformation via in situ absorption of the generated heat. The reversible capacity of NCM811 modified with 5 wt % of ZrW₂O₈ can remain at 180.6 mAh/g after 100 cycles at 60 °C and 1.0 C current rate, which increases the retention ratio of NCM811 by 14.8%, while the voltage difference between main redox peaks, R_ct, strain after cycles, and heat from DSC of NCM811 are reduced about 47.8%, 81.0%, 28.2%, and 76.0%, respectively. According to various analysis results, the side reactions are also suppressed, and the enhancing mechanisms of ZrW₂O₈ for NCM811 were discussed. A general strategy is developed for the management of deformation using heat to improve performance and safety of batteries.