P-Type Cross-Linked Silicon Nanocomposites for Improving the Lithium-Ion Deinsertion from Anode Materials of Lithium-Ion Batteries

Abstract

Silicon has been an extremely popular anode active material owing to its rather high theoretical specific capacity; however, volume distension and the generation of an unstable SEI film during the lithium insertion and deinsertion process severely limit its commercial development. Herein, a type of P-type cross-linked Si semiconductor rich in hole carrier nanocomposite (Si@SiC@PF) on the basis of B doping is synthesized via a facile vacuum direct current arc combined along with a high-temperature solid phase method. B doping can transform Si into a stable P-type semiconductor with a large number of hole carriers so as to effectively accelerate electron conduction on the Si surface and improve the deinsertion efficiency of lithium ions. In addition, we also discover that B doping also can optimize the distribution of SiC with a strong Si–C bond energy to allow it to aggregate on the surface of Si, resulting in the growth of the hierarchical structure, thus better exerting its buffering effect. Then, coating amorphous carbon through pyrolyzing phenolic resin (PF) can improve the conductivity of the composite material while providing ample space for accommodating the volume expansion of Si and forming a stabilized SEI film. As an anode active material for lithium-ion batteries, the specific discharge capacity still remains at 1272 mAh·g^–1 after 300 cycles.