Chemical Cross-linked Electrode-Electrolyte Interface Boosting the Structural Integrity of High Nickel Cathode Materials

High nickel cathode material LiNixCoyMn1-x-yO2 (NCM) (x >= 0.6) has represented the most critical material in virtue of outstanding specific capacity and low self-discharge. However, the high surface alkalinity and detrimental interfacial stability lead to the parasitic reaction and a series of phase deterioration. Herein, in situ cross-linking binder molecular chains with a 3D network structure to construct a stable and robust electrode-electrolyte interface, which can maintain the structural integrity and restrain side reactions is designed. Simultaneously, the cross-linked polymer can form stable hydrogen bonds with the pristine binder, greatly enhancing the bonding property. More importantly, the functional groups contained in the cross-linked co-polymers can chemically anchor transition metals, effectively preventing the dissolution of transition metals. Theoretical calculations confirm the feasibility and advancement of the anchoring mechanism, driving excellent structural stability and inhibition of the NiO impurity phase. This work provides a practical strategy to realize the high stability of cathode materials. Benefited from the 3D network structure of cross-linking binder molecular chains, a stable and robust electrode-electrolyte interface is constructed, which can maintain the structural integrity. Simultaneously, the cross-linked polymer can form stable hydrogen bonds with polyvinylidene fluoride, greatly enhancing the bonding property. More importantly, the functional groups contain can chemically anchor transition metals, effectively preventing the dissolution of transition metals.image