Self-assembly of porous-graphite/silicon/carbon composites for lithium-ion batteries

• Electrostatic attraction provides the driving force for self-assembly.
• We use porous-graphite replacing graphene to encapsulate silicon.
• The electrochemical performance of the composites have been improved.

The self-assembly of porous-graphite/silicon/carbon composites is fabricated by electrostatic attraction in solvent and pyrolysis method. Silicon carries a positive charge after surface modification and porous-graphite carries a negative charge after oxidation. Transmission electron microscopy reveals some Si nanoparticles encapsulated in pores of porous-graphite. X-ray diffraction shows that the structure of porous-graphite and silicon are not destroyed during oxidation of the graphite and surface modification of the silicon with APTES. Galvanostatic charge/discharge tests demonstrate that porous-graphite/silicon/carbon composites have much higher reversible charge capacity than flake graphite and better capacity retation than pristine silicon. The composites exhibit an initial reversible charge capacity of 778.8 mAh · g− 1.

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