LIQUID HOLDING BODY FOR LITHIUM SECONDARY BATTERIES, AND LITHIUM SECONDARY BATTERY

摘要

Provided are: a liquid holding body for lithium secondary batteries, which is capable of holding an electrolyte solution within an electrode or at the interface between the electrode and a separator, thereby preventing depletion of the electrolyte solution within the electrode, and which is also capable of suppressing deposition and growth of dendrite; and a lithium secondary battery which uses the liquid holding body for lithium secondary batteries and is capable of achieving cycle life that is suitable for industrial applications. A liquid holding body (3) for lithium secondary batteries, which is obtained by having an organic electrolyte solution permeate into or impregnated into an electrode group that is obtained by winding or laminating a positive electrode plate (2) and a negative electrode plate (1) with the liquid holding body (3) that serves as a separator being interposed therebetween. This liquid holding body (3) for lithium secondary batteries has a multilayer structure which has two hydrophilic fiber layers (A, B) that have different porosities. The porosity (40-80%) of the fiber layer (A) that is on the side of the interface with the negative electrode plate (1) is lower than the porosity (60-90%) of the fiber layer (B) that is on the side of the interface with the positive electrode plate (2), and the average porosity of these fiber layers as a whole is 50% or more. In addition, the fiber layers are mainly formed from a cellulose fiber, and the negative electrode active material used for the negative electrode plate (1) is a carbon material.