NOVELTY - Electrolyte solution comprises: a salt; a solvent; and substituted silicon-containing compound (I).    USE - The electrolyte solution is useful in battery (claimed) to supply power for consumer electronics, portable electronics, hybrid vehicles, electrical vehicles, power tools, power grid, military applications, and aerospace applications.    ADVANTAGE - The electrolyte solution: improves electrochemical stability in a high voltage battery at voltages above 4.2 V; improves electrochemical stability when the battery is operated in an environment at a temperature of 45 degrees C; exhibits high stability during battery cycling up to high temperatures, high voltages, high discharge capacity, and high coulombic efficiency, and excellent retention of discharge capacity and coulombic efficiency over several cycles of charging and discharging; and exhibits high rate capability, reduced electrolyte decomposition (thus mitigating loss of electrolyte, production of undesirable by-products, and gaseous by-products), reduced resistance and its build-up during cycling, and improved calendar life.    DETAILED DESCRIPTION - Electrolyte solution comprises: a salt; a solvent; and substituted silicon-containing compound of formula ((R1)(R2)(Si)(R3)(R4)) (I).    R1-R4 = 1-20C alkyl, 1-20C alkenyl, 1-20C alkynyl or 5-20C aryl (all optionally substituted by F).    An INDEPENDENT CLAIM is also included for a battery (100) comprising: an anode (102) comprising an anode active material having a first specific capacity; a cathode (106) comprising a cathode active material having a second specific capacity, where the first specific capacity and the second specific capacity are matched so that the battery has a rated charge voltage of greater than 4.2 V; the solvent; and an electrolyte solution comprising lithium salt, aqueous solvent, and (I).    DESCRIPTION OF DRAWING(S) - The figure illustrates the lithium-ion battery.    Battery (100)    Anode (102)    Electrolyte (104)    Cathode (106)    Separator (108)