NOVELTY - A secondary battery comprises an anode (5), a cathode (3), and an electrolyte. A compound (1) having a specific nitroxyl radical, is used in the anode and/or cathode as an active material.    USE - As lithium secondary battery (claimed) for portable electronic devices, such as notebook computers and mobile telephones.    ADVANTAGE - The secondary battery has excellent stability of charging-and-discharging cycle with high capacitance, and high energy density.    DETAILED DESCRIPTION - A secondary battery comprises an anode, a cathode, and an electrolyte. A compound of formula (1) having a specific nitroxyl radical, is used in the anode and/or cathode as an active material.    R 1,R 2,R 3 and/or R 4=group of formula (2), with other substituent being H, halogen atom, (un)substituted alkyl, (un)substituted aromatic hydrocarbon, (un)substituted aromatic heterocyclic group, (un)substituted alkoxy, (un)substituted aryloxy, or cyano.    R 5=(un)substituted alkyl, (un)substituted aromatic hydrocarbon, or (un)substituted aromatic heterocyclic group.    INDEPENDENT CLAIMS are included for the following:    1. Polymer having a repeating unit of formula (3 or 4).    R 1-R 4=as mentioned above; and    n=2 or more;    2. manufacture of polymer, which involves polymerizing ethynyl benzene derivative of formula (5), and reacting in a solvent with heavy metal oxide in the presence of a fluoride salt as a de-silyl agent.    R 6,R 7,R 8 and/or R 9=group of formula (6), with other substituent being H, halogen atom, (un)substituted alkyl, (un)substituted aromatic hydrocarbon, (un)substituted aromatic heterocyclic group, (un)substituted alkoxy, (un)substituted aryloxy, or cyano;and    X=halogen or trifluoromethyl sulfoxy;    R 5=as mentioned above;and    R 10=(un)substituted silicon protecting group; and    3. ethynyl benzene derivative of formula (5) and diethynyl benzene derivative of formula (10 or 11).    R 6-R 9=as mentioned above;and    R 11,R 12=R 10.    DESCRIPTION OF DRAWING(S) - The figure shows the conceptual diagram of the structure of battery. (Drawing includes non-English language text).    cathode collector (1)    insulation packing (2)    cathode (3)    separator (4)    anode (5)