| 摘要 |
<p>PROBLEM TO BE SOLVED: To relax the volume expansion of composite particles at charge and discharge and a stress caused by repetition of shrinkage, and to ensure a conducting path by carbon nanofiber (CNF) connecting between cracked composite particles even after cracking is caused by the repetition of a combination of volume expansion and shrinkage, thereby enhancing a discharge capacity and cycle characteristics.SOLUTION: A negative electrode active material 10 comprises: composite particles 11 including tin and cobalt; carbon nanofiber 12, a part of which is located in the composite particles and the other parts are located outside the composite particles; carbon nanofiber, all of which is located in the composite particles; and carbon nanofiber, all of which is located outside the composite particles. The composite particles each have a structure in which the tin is centered, and the cobalt is unevenly present, namely located on the external surface of the tin. The composite particles have an average particle diameter of 0.1-10μm. The mass percentage of the carbon nanofiber is 1-20 mass% to the total mass of the tin and cobalt.</p> |
