Patent ID: 8771873

Claim:
A lithium secondary battery comprising: a positive electrode; a negative electrode comprising a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector, the negative electrode active material layer comprising a binder and negative electrode active material particles containing silicon particles and/or silicon alloy particles; a separator interposed between the electrodes; and an electrode assembly comprising the positive electrode, the negative electrode, and the separator; and a non-aqueous electrolyte impregnated in the electrode assembly, wherein the binder contains a polyimide resin represented by the following chemical formula (1): where R in the chemical formula (1) is a functional group represented by the following chemical formula (2) or (3): and n is within the range of from 10 to 100,000; and the silicon particles and the silicon alloy particles have an average particle size of 5-25 μm.