Molten ion conductive salt/silicon interface for decreased interfacial resistance

A device comprising:

• a silicon based electrode composed of boron doped crystalline silicon;
• an interfacial additive layer composed of molten lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), wherein the interfacial additive layer has a first surface forming an interface with a surface of the silicon based electrode;
• and
• a solid polymer electrolyte layer composed of a mixture of polycaprolactone, succinonitrile and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) forming an interface with a second surface of the interfacial additive layer that is opposite the first surface of the interfacial additive layer.

A method of forming a device, the method comprising:

• depositing a layer of a lithium containing salt on a surface of a silicon based electrode;
• heating the layer of the lithium containing salt to a temperature that provides a molten lithium containing salt;
• cooling the molten lithium containing salt to provide an interfacial additive layer composed of the molten lithium containing salt;
• and
• forming a solid polymer electrolyte layer on the interfacial additive layer.