Porous, Encapsulated Si-O-C Lithium-Ion Battery Anode Materials from Silicone-Containing Polyesters: Influences of Graphene Oxides

Hydrophilic silicone-modified polyester (Si-PETs) were cured and thermally carbonized to give lithium-ion battery (LIB) anode materials (Si-O-C). Graphene oxides (GOs) were added to Si-PETs, and their effects were analyzed. A preloaded reductant, ascorbic acid, was also added for the purpose of transforming GO to reduced GO (rGO) after Si-PETs were cured. With the cured Si-PET matrix as the barrier, no rGO agglomeration was observed. It is interesting that during carbonization, the insolubility of rGO in Si-PET led to a porous structure, and the well-flexible rGO sheets could be crimped and could encapsulate silicon oxides. Well-dispersed rGO induced a homogeneous porous structure. As LIB anode materials, Si-O-C containing rGO (rGO/Si-O-C) presented higher specific capacities, more stable solid interface films (SEIs), and better cyclabilities. It is suggested that during the charge-discharge process, the porous structure alleviated the volume expansion of Si-O-C, and the encapsulation stabilized the SEI film, thus leading to better performances.