NOVELTY - A non-aqueous electrolyte contains pyridyl 5-membered heterocyclic derivative (I).    USE - Non-aqueous electrolyte is used for lithium secondary battery (claimed). Uses include but are not limited to notebook personal computer, mobile telephone, headphone stereo cassette tape recorder, liquid crystal television, electronic notebook, motorbike, electric motorcycle, bicycle, electric-power-assisted bicycle and game machine.    ADVANTAGE - The lithium secondary battery containing non-aqueous electrolyte has excellent durability and storing characteristics even at high temperature.    DETAILED DESCRIPTION - A non-aqueous electrolyte contains pyridyl 5-membered heterocyclic derivative of formula: Py-(Q)n (I).    Py=pyridyl group optionally substituted by 1-3 substituents chosen group (a);    Q=aromatic or non-aromatic 5-membered heterocyclic group having 1-4 oxygen, sulfur, or nitrogen, and optionally substituted by group (b);    groups a,b=phenyloxy, phenyl, aromatic 5-membered heterocyclic group or aromatic 6-membered heterocyclic group (all optionally substituted by halo or 1-6C alkyl), halo, 1-8C alkyl, 3-6C cycloalkyl, 2-6C alkenyl, 2-6C alkynyl, 1-8C alkoxy, 2-6C alkenyloxy, 2-6C alkynyloxy, 1-8C alkylthio, 1-8C alkyl sulfinyl, 1-8C alkylsulfonyl, 1-8C alkylamino, di-(1-8C)alkylamino which is bonded directly or through oxygen, sulfur or nitrogen, substituted by 1-6C alkyl, and the two alkyl groups optionally combine to form 3-7 membered ring, nitro, formyl, cyano, carboxy, alkoxycarbonyl in which the alkyl is 1-8C alkyl, carbamoyl, N-(1-8C)alkylamino carbonyl, or N,N-di-(1-8C)alkylamino carbonyl which is bonded directly or through oxygen, sulfur or nitrogen, substituted by 1-6C alkyl, and the two alkyl groups optionally combine to form 3-7 membered ring;and    n=1 or 2.    An INDEPENDENT CLAIM is included for lithium secondary battery, which has positive electrode (1) containing metallic lithium, lithium containing alloy, and metal in which alloying with lithium is possible, negative electrode (2) containing negative electrode active material including alloy in which alloying with lithium is possible, oxide in which dope and dedope of a lithium ion are possible, transition-metal nitrided material in which dope and dedope of lithium ion is possible, and carbon material in which dope and dedope of lithium ion is possible, and non-aqueous electrolyte.    DESCRIPTION OF DRAWING(S) - The drawing shows sectional view of lithium secondary battery.    Positive electrode (1)    Negative electrode (2)    Positive electrode can (3)    Sealing board (4)    Separator (5)