NOVELTY - Solid electrolyte comprises: an interpenetrating polymer network comprising alkene-oxide compound, where the interpenetrating polymer network is substantially formed by polymerizing a first monomer, a second monomer and an initiator; and a lithium salt dispersed in the interpenetrating polymer network, where the molecular weight of the first monomer or the second monomer is 100-800, the first monomer is less than or equal to 50 wt.% of the second monomer, and the lithium salt is less than or equal to 10 wt.% of the second monomer.    USE - The solid electrolyte is useful in a lithium based battery (claimed), which is useful in electric vehicles and portable electronic devices such as mobile phones, digital cameras and notebook computers.    ADVANTAGE - The solid electrolyte exhibits good thermal stability, electrochemical stability and high ionic conductivity thus providing the lithium based battery with high life span, high power and good stability and safety.    DETAILED DESCRIPTION - Solid electrolyte comprises: an interpenetrating polymer network comprising alkene-oxide compound of formula (-(CH2-CH2-O)n-), where the interpenetrating polymer network is substantially formed by polymerizing a first monomer of formula (R1-O-(CH2-CH2-O)n-R2), a second monomer of formula (R3-O-(CH2-CH2-O)m-R4) and an initiator; and a lithium salt dispersed in the interpenetrating polymer network, where the molecular weight of the first monomer or the second monomer is 100-800, the first monomer is less than or equal to 50 wt.% of the second monomer, and the lithium salt is less than or equal to 10 wt.% of the second monomer.    R1-R3 = -C=C- group or -CC- group;    R4 = alkyl or H; and    m, n = integers.    An INDEPENDENT CLAIM is included for a lithium based battery comprising an anode (110), a cathode (130), and the solid electrolyte attached between the anode and the cathode.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a lithium based battery.    Anode (110)    Cathode (130)    Anode collector (112)    Anode material layer (114)    Cathode collector. (132)