| 摘要 |
PROBLEM TO BE SOLVED: To provide a novel silicon-containing negative electrode active material particle which enables the enhancement in battery cycle characteristic.SOLUTION: A negative electrode active material particle comprises silicon, oxygen and boron. In the negative electrode active material particle, the oxygen and boron are both inclined in concentration; a part including the silicon, oxygen and boron involves an amorphous phase, and a part including the silicon, oxygen and boron involves a porous phase. The oxygen and boron are included only in the surface of the negative electrode active material particle, or included in the whole negative electrode active material particle. In the surface of the negative electrode active material particle, the content of the boron to the total amount of the silicon, oxygen and boron is 1-50 atom%. A method for manufacturing a negative electrode active material particle comprises the step of doping a silicon-containing particle with oxygen and boron by a thermal treatment. The thermal treatment is performed at a doping temperature between 600 and 900°C, inclusive of 600°C, for 1-10 hours, thereby doping only the surface of the particle with the oxygen and boron, or it is performed at 900-1000°C for 0.1-24 hours, thereby doping the particle to a predetermined depth thereof or doping the whole particle.SELECTED DRAWING: Figure 1 |
