Non-aqueous electrolytic solution and lithium secondary battery

Abstract

A non-aqueous electrolytic solution favorably employable for a lithium secondary battery employs a non-aqueous electrolytic solution which comprises a non-aqueous solvent and an electrolyte which further contains 0.001 to 0.8 weight % of a biphenyl derivative having the formula: in which each of Y 1 and Y 2 represents hydroxyl, alkoxy, hydrocarbyl, hydrogen, acyloxy, alkoxycarbonyloxy, alkylsulfonyloxy, or halogen, and each of p and q is an integer of 1 to 3.

1 . (canceled)  
     
     
         2 . (canceled)  
     
     
         3 . (canceled)  
     
     
         4 . (canceled)  
     
     
         5 . (canceled)  
     
     
         6 . (canceled)  
     
     
         7 . (canceled)  
     
     
         8 . (canceled)  
     
     
         9 . (canceled)  
     
     
         10 . (canceled)  
     
     
         11 . A method of operating a lithium secondary battery in a voltage range having a maximum operating voltage exceeding 4.2 V, the lithium secondary battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolytic solution comprising a cyclic cargonate, a linear chain carbonate and an electrolyte which further contains 0.001 to 0.8 weight % of a biphenyl derivative selected from the group consisting of biphenyl, 4-methoxybiphenyl, 4-hydroxybiphenyl, o-terphenyl, 4-biphenylyl acetate, 4-biphenylyl methylcarbonate, and 4-methanesulfonyloxybiphenyl.  
     
     
         12 . The method of  claim 11 , wherein the amount of the biphenyl derivative is in the range of 0.01 to 0.5 weight %.  
     
     
         13 . The method of  claim 11 , wherein the biphenyl derivative is biphenyl.  
     
     
         14 . The method of  claim 11 , wherein the non-aqueous electrolytic solution furthermore contains at least one compounds selected from the group consisting of triethyl phosphate, tributyl phosphate, trioctyl phosphate, vinylene carbonate, and 1,3-propanesultone.