NOVELTY - An electrolyte composition comprises aprotic organic solvent(s) (A), organolithium compound (B) (I), and optionally contains conducting salt(s) (C) different from component (B), and additive(s) (D).    USE - Electrolyte composition is used for electrochemical cell e.g. lithium-ion battery (all claimed) for stationary power storage and mobile device. Uses include but are not limited to automobiles, bicycles, aircraft, boats and ships, electrical power tools, battery-driven screwdrivers and battery-driven tackers for use in construction sector, and laptops and telephones.    ADVANTAGE - The economical nonaqueous electrolyte composition has excellent durability and wettability, and provides lithium-ion battery having excellent cycle characteristics, discharge capacity and energy density. The conducting salt contained in the electrolyte composition has excellent corrosion resistance with respect to current collector materials, solubility, electrochemical stability, thermal stability, ion mobility and compatibility with respect to other components of electrolyte composition, and low reactivity and toxicity, and does not interact with electrode materials such as binders, conductive carbon black and electrode active material.    DETAILED DESCRIPTION - An electrolyte composition comprises aprotic organic solvent(s) (A), organolithium compound (B) of formula (I), and optionally contains conducting salt(s) (C) different from component (B), and additive(s) (D).    Z=Al or B;    R1-R4=C(O)R5, or 1-10C alkyl, 2-10C alkenyl, 2-10C alkynyl, 3-10C cycloalkyl, 6-14C aryl or 5-14C heteroaryl (all optionally substituted by F and/or optionally fluorinated 1-4C alkyl, 2-4C alkenyl, 2-4C alkynyl, phenyl or benzyl);    or R1,R2=C(O) or 1-3C alkylene optionally substituted by one or more F, and/or by optionally fluorinated 1-4C alkyl, phenyl or benzyl;    or R1+R2+joining group(OZO)=5-7-membered heterocyclyl;and    R5=1-10C alkyl, 2-10C alkenyl, 2-10C alkynyl, 3-10C cycloalkyl, 6-14C aryl or 5-14C heteroaryl (all optionally substituted by F and/or optionally fluorinated 1-4C alkyl, phenyl or benzyl).    (i) At least one of R1-R4 carries at least one F. INDEPENDENT CLAIMS are included for the following:    (1) usage of organolithium compound (I) as conducting salts for electrolytes in electrochemical cells; and    (2) electrochemical cell, which has the electrolyte composition, cathode(s) comprising a cathode active material, and anode(s) comprising an anode active material.