LITHIUM-ION SECONDARY CELL

摘要

Provided is a lithium-ion secondary cell that makes it possible to increase flame retardance and improve cell charging load characteristics and cycle characteristics. A phosphazene compound represented by chemical formula (1) (where at least one of R1-R6 is an ethoxy group and the remainder are halogens) is compounded in a non-aqueous electrolyte. A carbonaceous material in which the d value (spacing) of the lattice plane (002-plane) obtained by X-ray diffraction using the method specified by the Japan Society for the Promotion of Science is 0.340-0.370 nm is used as a carbonaceous substance contained in the negative electrode active material.