Abstract: The present disclosure provides a negative electrode for use in a lithium-ion secondary battery capable of protecting the negative electrode from breakage and cracks due to expansion and contraction of an Si-based negative electrode active material. The negative electrode is for use in a lithium-ion secondary battery and includes 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 contains, as a negative electrode active material, an Si-based negative electrode active material including Si as a component and capable of reversibly absorbing and releasing lithium ions. The negative electrode further includes a high-molecular-weight organic compound for improving durability of the lithium-ion secondary battery. The high-molecular-weight organic compound has a weight-average molecular weight of 1000 or higher.

Abstract: A nonaqueous electrolyte for use in a lithium-ion secondary battery, capable of reducing gas generation due to degradation of nonaqueous electrolyte, is provided. The nonaqueous electrolyte disclosed herein is for use in a lithium-ion secondary battery wherein a negative electrode active material in a negative electrode includes at least one of a Si-based negative electrode active material including Si as a component and capable of reversibly absorbing and releasing lithium ions or a graphite-based carbon negative electrode active material. The nonaqueous electrolyte contains a nonaqueous solvent and an electrolyte dissolved in the nonaqueous solvent, and further contains a cyclic carbonate and a high-molecular-weight organic compound having a weight-average molecular weight of 1000 or higher.

Abstract: This invention relates to a laser marking method which comprises heating a base article having on its surface a thin film of a laser marking composition containing a color former and a color developer having a melting point of 200.degree. C. or above, and then applying laser light to the thin film. The method of this invention is capable of no-break marking with vivid color development by application of laser light, without causing discoloration of the ground even under a condition of 120.degree. C. or above.

Abstract: This invention relates to a laser marking method which comprises coating a laser marking composition containing as essential components a color former, a color developer and an inorganic compound having the absorption peak on the infrared absorption spectrum in the region of 900-1,000 cm.sup.-1 on a substrate to form a color developing layer, and irradiating laser light to the color developing layer; the laser marking composition; and articles having a color developing layer made of the laser marking composition. The method of this invention is capable of forming a mark with vivid color development even when the color developing layer is a thin film of less than 5 .mu.m in thickness or when marking is carried out at high speed.