The present invention provides a composite composition comprising silicon fine particles, and a silicon dioxide (SiO x , where x is 1/2, 1 and 3/2) covering at least a part of the surface of the silicon fine particles and / Or a mixed composition of the secondary silicon oxide and silicon dioxide.本發明係提供一種複合組成物,其包含矽微粒子,以及包覆該矽微粒子的表面之至少一部分的次氧化矽(SiOx,式中的x係1/2、1以及3/2)及/或該次氧化矽與二氧化矽的混合組成物。