Electrolyte for electrochemical device, method for preparing the electrolyte and electrochemical device including the electrolyte
Disclosed is an electrolyte for an electrochemical device. The electrolyte includes a composite of a plastic crystal matrix electrolyte doped with an ionic salt and a crosslinked polymer structure. The electrolyte has high ionic conductivity comparable to that of a liquid electrolyte due to the use of the plastic crystal, and high mechanical strength comparable to that of a solid electrolyte due to the introduction of the crosslinked polymer structure. Further disclosed is a method for preparing the electrolyte. The method does not essentially require the use of a solvent. Therefore, the electrolyte can be prepared in a simple manner by the method. The electrolyte is suitable for use in a cable-type battery whose shape is easy to change due to its high ionic conductivity and high mechanical strength.
1. A method for preparing a solid electrolyte comprising a composite of a composite of a plastic crystal matrix electrolyte doped with an ionic salt and a crosslinked polymer structure, the method comprising:
(S1) mixing the plastic crystal matrix electrolyte doped with the ionic salt and a monomer having two or more crosslinkable functional groups to prepare a solution; and
(S2) polymerizing only the monomer of the solution to form the crosslinked polymer structure in the presence of the plastic crystal matrix electrolyte.
2. The method according to claim 1 , wherein the ionic salt-doped plastic crystal matrix electrolyte and the monomer are used in a weight ratio of 30:70 to 90:10.
3. The method according to claim 1 , wherein the plastic crystal matrix electrolyte comprises succinonitrile.
4. The method according to claim 1 , wherein the ionic salt is used in an amount of 0.1 to 3 moles per mole of the plastic crystal matrix electrolyte.
5. The method according to claim 1 , wherein the ionic salt is a lithium salt.
6. The method according to claim 5 , wherein the lithium salt is selected from lithium bis-trifluoromethanesulfonylimide, lithium bis-perfluoroethylsulfonylimide, lithium tetrafluoroborate, and mixtures thereof.
7. The method according to claim 1 , wherein the monomer having two or more functional groups is selected from trimethylolpropane ethoxylate triacrylate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, ethoxylated bisphenol A dimethacrylate, ethylene glycol diacrylate, and mixtures thereof.