Intermediate for porous silicon oxycarbide, method for its preparation, and lithium secondary battery comprising the porous silicon oxycarbide as an anode active material

Porous SiOC Anode Material Based on Pyrolysis of POSS-Cage Crosslinked Polysiloxane Intermediates

This technology utilizes an intermediate for creating a porous silicon oxycarbide (SiOC) with a 3D network structure. By introducing cage-structured POSS moieties between linear polysiloxane backbones, it ensures the formation of uniform nanopores within the SiOC matrix after pyrolysis.

Conventional silicon-based anode materials undergo 300–400% volume expansion during lithiation, leading to physical particle fracture and loss of electrical contact. Additionally, excessive SEI layer formation has historically caused electrochemical performance degradation.

This technology synthesizes a crosslinked intermediate via hydrosilylation of linear polysiloxane, aromatic compounds, and POSS moieties, which is then pyrolyzed to form a porous SiOC structure. The steric hindrance of POSS inhibits carbon cluster growth and creates numerous internal pores, securing ion diffusion pathways. Applicable to high-capacity silicon-based anodes for smartphones, laptops, and long-range EV cells, it achieves higher capacity than graphite while mitigating electrode delamination caused by expansion.

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Key Features:

• Linear polysiloxane backbone forming a 3D network structure in the intermediate for porous silicon oxycarbide production
• Cage-structured POSS moiety disposed between linear polysiloxane backbones, contained at less than 3 parts by weight per 100 parts by weight of the intermediate
• Organosilicon bonds connecting polysiloxane polymers and linking polysiloxane with POSS via arylene groups
• Step of hydrosilylation reaction of linear polysiloxane, POSS, and aromatic compounds substituted with two or more vinyl or acetylene groups

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This invention was developed with support from the Ministry of Education’s research on biomimetic nanosensor systems.

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