GELLED ELECTROLYTE AND PREPARATION METHOD THEREOF

A gel composition, in particular a gelled electrolyte, comprising: i) fumed alumina particles, wherein the mean primary particle size of the particle is from 5 to 50 nm and the BET specific surface area is from 40 to 400 m/g; ii) at least two organic solvents; and iii) a lithium salt; wherein the amount of the alumina particles is 0.2-10% by weight based on the total weight of the gel composition. A method to prepare a gelled electrolyte, a Li-ion battery, a Li-ion battery and a device are also provided.