BINDER FOR ELECTRODE OF ELECTROCHEMICAL ELEMENT, COMPOSITION FOR ELECTRODE OF ELECTROCHEMICAL ELEMENT, ELECTRODE OF ELECTROCHEMICAL ELEMENT AND ELECTROCHEMICAL ELEMENT

1 .- 9 . (canceled)

10 . A binder for an electrode of an electrochemical element, wherein the binder is a polymer having an N-vinyl formamide unit.

11 . The binder for an electrode of an electrochemical element of claim 10 , wherein the content of the N-vinyl formamide unit in the polymer is 10 mol % to 100 mol %.

12 . The binder for an electrode of an electrochemical element of claim 10 , wherein the binder is water-soluble.

13 . The binder for an electrode of an electrochemical element of claim 10 , wherein the content of the N-vinyl formamide unit in the polymer is 50 mol % to 100 mol %.

14 . The binder for an electrode of an electrochemical element of claim 10 , wherein the viscosity average molecular weight of the polymer is 10,000 to 10 million.

15 . The binder for an electrode of an electrochemical element of claim 10 , wherein the viscosity average molecular weight of the polymer is 10,000 to 8 million.

16 . The binder for an electrode of an electrochemical element of claim 10 , wherein the viscosity average molecular weight of the polymer is 50,000 to 5 million.

17 . The binder for an electrode of an electrochemical element of claim 10 , wherein the oxidation current value obtained with the cyclic voltammetry of Condition I below is 2 mA/g or less;

<Condition I>

using a three-electrode electrolytic cell of the following specification, the current value of the first cycle is determined with a scan speed of 1 mV/s and a scan range of 3.5 V to 5 V; the oxidation current value is obtained by dividing the current value at a voltage value of 4.8 V by the mass of a working electrode;

{Specification of Three-Electrode Electrolytic Cell}

working electrode: an electrode of a mixture layer containing 1 part by mass of a binder for an electrode and 1 part by mass of acetylene black is disposed between an aluminum foil and an aluminum mesh;

reference electrode: a lithium foil;

counter electrode: a lithium foil;

electrolyte solution: 1 mol/L of a hexafluorophosphate lithium solution (solvent: ethylene carbonate/diethyl carbonate=1/2 (volume ratio)).

18 . The binder for an electrode of an electrochemical element of claim 10 , wherein the reduction current value obtained with the cyclic voltammetry of Condition II below is 5 mA/g or less;

<Condition II>

using a three-electrode electrolytic cell of the following specification, the current value of the first cycle is determined with a scan speed of 1 mV/s and a scan range of 3 V to 0 V; the reduction current value is obtained by dividing a current value at a voltage value of 0.5 V by the mass of a working electrode;

{Specification of Three-Electrode Electrolytic Cell}

working electrode: an electrode of a mixture layer containing 1 part by mass of a binder for an electrode and 1 part by mass of acetylene black is disposed between an aluminum foil and an aluminum mesh;

reference electrode: a lithium foil;

counter electrode: a lithium foil;

electrolyte solution: 1 mol/L of a hexafluorophosphate lithium solution (solvent: ethylene carbonate/diethyl carbonate=1/2 (volume ratio)).

19 . A composition for an electrode of an electrochemical element, wherein the composition contains the binder for an electrode of an electrochemical element of claim 10 .

20 . An electrode for an electrochemical element, including a current collector and a mixture layer disposed on the current collector, wherein the mixture layer contains the composition for an electrode of an electrochemical element of claim 19 and an electrode active material.

21 . An electrochemical element, including the electrode for an electrochemical element of claim 20 .