Abstract: In this paper, lithium stored silicon were prepared with the electrochemical reaction method. The electron spin resonance (ESR) signals of silicon and lithium-stored silicon were measured. The ESR intensity of silicon showed a linear change with the reciprocal of the temperature, indicative of the presence of Curie spins, which may come from localized spin centers, such as crystal defects and hanging bonds on the surface. In lithium-stored silicon, however, both Pauli spins and Curie spins were shown to be present. The amplitude of integrated ESR signals owing to Curie spins in lithium-stored silicon was 2~3 times higher than that in silicon. The effects of temperature on the g factor and line width (ΔH_pp) of the ESR signals were also investigated. It could be concluded that when lithium ion reacts with silicon in the electrochemical reaction, compensating electrons from the external circuit mostly took part in forming the covalent bonds between Li and Si, and contributed little to the ESR intensity.

Key words: ESR, electrochemistry, silicon, lithium-stored silicon