Abstract: There are provided a novel onium salt and a method for optimizing the interface of a negative electrode by the use of the novel onium salt and/or a conventional onium salt. Such a method is characterized in that an electrolyte comprising novel 2,2,2-trifluoro-N-(trifluoromethanesulfonyl)acetamide•tetraethyl ammonium salt is made to intervene between a negative electrode and a positive electrode in an electrochemical device having the constitution: a negative electrode|an electrolyte|a positive electrode, thereby constructing an electrode structure in the electrochemical device, and applying a voltage between the negative electrode and the positive electrode so as for the negative electrode to have a potential of ?1 V to ?5 V in terms of the potential relative to a reference electrode of I?/I3?, thereby forming a passive-state layer comprising a decomposition product of the above electrolyte or salt on the surface of the above negative electrode.

Abstract: There are provided a novel onium salt and a method for optimizing the interface of a negative electrode by the use of the novel onium salt and/or a conventional onium salt. Such a method is characterized in that an electrolyte comprising novel 2,2,2-trifluoro-N-(trifluoromethanesulfonyl)acetamide.tetraethyl ammonium salt is made to intervene between a negative electrode and a positive electrode in an electrochemical device having the constitution: a negative electrode| an electrolyte| a positive electrode, thereby constructing an electrode structure in the electrochemical device, and applying a voltage between the negative electrode and the positive electrode so as for the negative electrode to have a potential of ?1 V to ?5 V in terms of the potential relative to a reference electrode of I?/I3?, thereby forming a passive-state layer comprising a decomposition product of the above electrolyte or salt on the surface of the above negative electrode.

Abstract: The present invention can provide an anion exchange type separation membrane used for direct liquid fuel type fuel cell, high in heat resistance, hard to deteriorate when using and capable of obtaining high battery output. A composite membrane used as the separation membrane for fuel cell can be obtained by using a porous film, composed of a hydrolysis resistant polyimide resin such as a polyimide resin having a fluorenylidene group in a main framework, as a substrate; optionally increasing water retention characteristics for example by applying a water-retentive resin to at least a part of a surface of the porous film; and then filling an anion-exchange resin such as a cross-linked hydrocarbon-based anion-exchange resin having a quaternary ammonium group as an anion exchange group into a void portion of the porous film.

Abstract: There are provided a novel onium salt and a method for optimizing the interface of a negative electrode by the use of the novel onium salt and /or a conventional onium salt. Such a method is characterized in that an electrolyte comprising novel 2, 2, 2-trifluoro-N-(trifluoromethanesulfonyl) acetamide·tetraethyl ammonium salt is made to intervene between a negative electrode and a positive electrode in an electrochemical device having the constitution: a negative electrode|an electrolyte |a positive electrode, thereby constructing an electrode structure in the electrochemical device, and applying a voltage between the negative electrode and the positive electrode so as for the negative electrode to have a potential of ?1 V to ?5 V in terms of the potential relative to a reference electrode of I?/I3?, thereby forming a passive-state layer comprising a decomposition product of the above electrolyte or salt on the surface of the above negative electrode.

Abstract: There are provided a novel onium salt and a method for optimizing the interface of a negative electrode by the use of the novel onium salt and/or a conventional onium salt. Such a method is characterized in that an electrolyte comprising novel 2,2,2-trifluoro-N-(trifluoromethanesulfonyl) acetamide•tetraethyl ammonium salt is made to intervene between a negative electrode and a positive electrode in an electrochemical device having the constitution: a negative electrode | an electrolyte | a positive electrode, thereby constructing an electrode structure in the electrochemical device, and applying a voltage between the negative electrode and the positive electrode so as for the negative electrode to have a potential of −1 V to −5 V in terms of the potential relative to a reference electrode of I−/I3−, thereby forming a passive-state layer comprising a decomposition product of the above electrolyte or salt on the surface of the above negative electrode.