NOVELTY - A negative electrode (3) comprises negative electrode active material and film-forming additive. The content of film-forming additive is 0.001-5 %mass negative electrode active material with respect to negative electrode active material. The film-forming additive comprises oxetane compound chosen from oxetane compounds (I) and (II).    USE - Negative electrode is used for lithium-ion secondary battery for assembled battery as motor driving power supply of vehicle (all claimed) e.g. hybrid vehicle, and for mobile telephone and notebook personal computer.    ADVANTAGE - The negative electrode having excellent storage stability and long-term reliability is manufactured by economical process, and provides secondary battery with excellent cycle characteristics and storage characteristics.    DETAILED DESCRIPTION - A negative electrode comprises negative electrode active material and film-forming additive. The content of film-forming additive is 0.001-5 %mass negative electrode active material with respect to negative electrode active material. The film-forming additive comprises oxetane compound chosen from oxetane compounds of formulae (I) and (II).    R1=H or 1-5C alkyl;    R2=OH, -O-X, -O-C(=O)X, -O-C(=O)-O-X, -O-C(=O)-NH-X, -O-P(=O)(OCaH2a+1)2, -O-P(OCbH2b+1)2 or -O-P(=O)(OCcH2c+1)(CdH2d+1);    X=alkyl, alkenyl or phenyl;    a-d=1-10;    R3,R4=H, CH3 or C2H5;    R5=O, -O-Y'-O-, -O-C(=O)-Y'-C(=O)-O-, -O-C(=O)-NH-Y'-NH-C(=O)-O-, (O-C6H4)q, (O-CH2-C6H4-CH2)n-O-,-O-P(=O)(OCsH2s+1)-O-, -O-P(OCmH2m+1)-O-, -O-P(=O)(CtH2t+1)-O- or -O-P(-C6H5)-O-;    q,n=1-5;    s,m,t=1-10;    Y'=-CpH2p-, cyclohexylenyl, alkenylenyl, -(C6H4)r-, -(CuH2u-O)x-, -(CH2-CH2-O)k-CH2-CH2- or -C(=O)-;    k=0-3;    p,u=m;and    r,x=q.    INDEPENDENT CLAIMS are included for the following:    (1) lithium-ion secondary battery, which has negative electrode;    (2) assembled battery;    (3) vehicle, which comprises lithium-ion secondary battery as motor driving power supply; and    (4) manufacture of negative electrode, which involves preparing slurry containing film-forming additive and negative electrode active material, applying the slurry on an anode collector, and drying. The film-forming additive is chosen from oxetane compound(s), binder and dispersion solvent.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the structure of electrode element.    Positive electrode (1)    Separator (2)    Negative electrode (3)    Negative electrode active material layer (3a)    Positive electrode terminal (4)