A scalable one-pot strategy for the development of polymer electrolytes adaptable to room-temperature high-voltage lithium batteries

Poly(ethylene oxide)(PEO)polymer electrolytes(PEs)have been commercially applied in LiFePO_(4)||Li solid-state lithium batteries(SSLBs).However,it remains challenging to develop PEO-based PEs applicable to the high-voltage SSLBs with higher energy density,owing to the poor electrochemical stability of PEO.Herein,we report a scalable strategy for fabricating PEO-based PEs with high-voltage compatibility,by exploiting a new mechanism to stabilize the cathode-electrolyte interface in the highvoltage SSLBs.The protocol only involves a one-pot synthesis procedure to covalently crosslink the PEO chains,in the presence of high-content lithium bis(trifluoromethylsulphonyl)imide(LiTFSI)salts and N,N-dimethylformamide(DMF).LiTFSI-DMF supramolecular aggregates are formed and firmly embedded in the polymer network,endowing the PE with high room-temperature ionic conductivity.The dissociated and highly concentrated TFSI^-anions can enter the Helmholtz layer close to the high-voltage cathode,leading to the formation of a thin and homogeneous cathode electrolyte interface(CEI),mainly composed of LiF,on the cathode.The CEI with high electrochemical stability can effectively stabilize the cathode-electrolyte interface,enabling long-term stable cycling of the high-voltage LiCoO_(2)||Li and nickelrich NCM_(622)||Li batteries at room temperature.The simplicity and scalability of the strategy makes the reported PEO-based PE potentially applicable in high-voltage SSLBs in practice.

Highly Stretchable and Elastic Polymer Electrolytes with High Ionic Conductivity and Li-Ion Transference Number for High-Rate Lithium Batteries

The ever-growing demand for wearable electronics drives the development of stretchable lithium-ion batteries(LIBs)with fast charging capability,in which stretchable polymer electrolytes(PEs)with high ionic conductivity and lithium-ion transference numbers(urn:x-wiley:1001604X:media:cjoc202200287:cjoc202200287-math-0001)are highly desirable.Herein,we report a highly stretchable and elastic PE with high ionic conductivity and urn:x-wiley:1001604X:media:cjoc202200287:cjoc202200287-math-0001,which is applicable in high-rate and stretchable LIBs.The PE was fabricated by incorporating polyethylene glycol(PEG)and lithium salts into polyurethane networks,whereinα-cyclodextrin(α-CD)acts as the cross-linker.The PEG chains are cross-linked by covalent and noncovalent bonds,and some PEG chains enter into the cavity ofα-CD to form PEG/α-CD inclusions.These structural features effectively suppress crystallization of the PEG chains,hinder movement of the counterions of Li+,and endow PE with satisfactory mechanical robustness.