Silicon-containing material and secondary-battery active material including silicon-containing material
Providing a silicon-containing material having a novel structure being distinct from the structure of conventional silicon oxide disproportionated to use. A silicon-containing material according to the present invention includes at least the following: a continuous phase including silicon with Si—Si bond, and possessing a bubble-shaped skeleton being continuous three-dimensionally; and a dispersion phase including silicon with Si—O bond, and involved in an area demarcated by said continuous phase to be in a dispersed state.
1. A silicon-containing material being obtained by a production process including a charging/discharging process in a set of two cycles or more wherein cation sorbing and desorbing are carried out to disproportionated silicon monoxide with a constant current and/or at a constant voltage with a C rate of from 1C or more to 4C or less and within a voltage range of from 3.6 V to 4.2 V at a temperature of from 35° C. or more to 80° C. or less, the silicon-containing material including at least:
a continuous phase including silicon with Si—Si bond, and possessing a bubble-shaped skeleton being continuous three-dimensionally; and
a dispersion phase including silicon with Si—O bond, and involved in an area demarcated by said continuous phase to be in a dispersed state.
2. The silicon-containing material as set forth in claim 1 , where said production process includes said charging/discharging process in a set of from 10 to 20 cycles.
3. The silicon-containing material as set forth in claim 1 , wherein
said continuous phase includes one or more members selected from the group consisting of elementary-substance silicon, and silicon-based compounds,
said dispersion phase includes a silicon oxide-based compound.
4. The silicon-containing material as set forth in claim 3 , wherein
said silicon-based compounds include an Si—Li compound,
said silicon oxide-based compound includes one or more members selected from the group comprising Si—O compounds, and Li—Si—O compounds.
5. The silicon-containing material as set forth in claim 4 , wherein
said Si—O compounds include one or more members selected from the group consisting of SiO 2 , and SiO x (where “x” falls in a range of 0.5≤“x”≤1.5),
said Li—Si—O compounds include one or more members selected from the group consisting of Li 2 SiO 3 , Li 4 SiO 4 , Li 2 Si 2 O 5 , Li 6 Si 2 O 7 , Li 2 Si 3 O 7 , and Li 8 SiO 6 .
6. The silicon-containing material as set forth in claim 1 , wherein
said continuous phase includes an elementary substance of silicon,
said dispersion phase includes a silicon oxide.
7. The silicon-containing material as set forth in claim 1 comprising a powder including silicon-containing particles including said continuous phase and said dispersion phase.
8. The silicon-containing material as set forth in claim 1 , wherein
said dispersion phase is composed of a plurality of fine particles retained in said area demarcated by said continuous phase,
the fine particles have an average particle diameter of from 0.05 to 50 nm.
9. The silicon-containing material as set forth in claim 1 being able to sorb and desorb lithium therein and therefrom, and having SiO n (where 0.5≤“n”≤3) as a fundamental composition.
10. An active material for secondary battery, the active material including the silicon-containing material as set forth in claim 1 .
11. A negative electrode for secondary battery, the negative electrode including the active material for secondary battery as set forth in claim 10 .
12. A secondary battery comprising:
a positive electrode;
the negative electrode as set forth in claim 11 ; and
a nonaqueous-system electrolytic solution.