A composite gel polymer electrolyte with high voltage cyclability for Ni-rich cathode of lithium-ion battery

• A novel type GPE material based on PECA was developed
• The cyclability of Li[Ni0.5Co0.2Mn0.3]O2/graphite full cell was improved at elevated cut-off potential.
• The GPE can prevent the Mn2+ deposition on the anode surface.

In order to overcome severe capacity fading of Ni-rich layered oxides Li[Ni1 -x-yCoxMny]O2 cathode of lithium-ion battery at elevated voltage, a composite membrane consisting of poly(ethylene terephthalate) (PET) nonwoven fabric incorporated with poly(ethyl α-cyanoacrylate) was investigated as polymer matrix of gel polymer electrolyte (GPE). The ionic conductivity of the GPE based on this composite membrane saturated with a liquid electrolyte (LE) of 1 M LiPF6 in carbonate solvents is 2.54 mS cm− 1 at room temperature, and the stable electrochemical voltage window can be up to 4.7 V. Its electrochemical performance is evaluated by using full cell with Li[Ni0.5Co0.2Mn0.3]O2 as cathode and graphite as anode. These results demonstrate that the as-prepared GPE remarkably improves the cyclability at the high cut-off voltage compared to the commercial liquid electrolyte.