SILICON-BASED ENERGY STORAGE DEVICES WITH CYCLIC CARBONATE CONTAINING ELECTROLYTE ADDITIVES

1 . An energy storage device comprising:

a first electrode and a second electrode, wherein at least one of the first electrode and the second electrode is a Si-based electrode;

a separator between the first electrode and the second electrode;

an electrolyte;

at least one electrolyte additive comprising a compound selected from the group consisting of 4-(Trifluoromethyl)-1,3-dioxolan-2-one (TFPC); 4,4-Bis(trifluoromethyl)-1,3-dioxolan-2-one (including cis, trans and racemate forms); 4,5-Bis(Trifluoromethyl)-1,3-dioxolan-2-one; 1,1,2-Tris(trifluoromethyl)ethylene carbonate; Tetrakis(trifluoromethyl)ethylene carbonate; 4-(Fluoromethyl)-1,3-dioxolan-2-one; 3,3-Difluoropropylene carbonate; 4-[(2,2,2-Trifluoroethoxy)methyl]-1,3-dioxolan-2-one; 4-[(2,2,3,3,3-Pentafluoropropoxy)methyl]-1,3-dioxolan-2-one; and 3-[(2,2,3,3-Tetrafluoropropoxy)methyl]-1,3-dioxolan-2-one; and

wherein said electrolyte additive is present at a concentration from about 0.5 wt % to about 9 wt %.

2 . The energy storage device of claim 1 , wherein the second electrode is a Si-dominant electrode.

3 . The energy storage device of claim 1 , wherein the second electrode comprises a self-supporting composite material.

4 . The energy storage device of claim 3 , wherein the composite material comprises:

greater than 0% and less than about 90% by weight of silicon particles, and

greater than 0% and less than about 90% by weight of one or more types of carbon phases, wherein at least one of the one or more types of carbon phases is a substantially continuous phase that holds the composite material together such that the silicon particles are distributed throughout the composite material.

5 . The energy storage device of claim 1 , wherein the electrolyte further comprises fluoroethylene carbonate (FEC).

6 . The energy storage device of claim 5 , wherein the electrolyte is substantially free of non-fluorine containing cyclic carbonate.