This approach uniquely integrates mechanochemical reduction with composite engineering, leveraging the dual functionality of the B₂O₃ byproduct to modulate electrolyte accessibility and conductivity through selective leaching or retention. By avoiding high-temperature silicide formation, it reduces energy consumption and enables scalable production of Si/graphite/CNT nanocomposites. The pyrolyzed polymer matrix forms a robust amorphous carbon interface, while carbon nanotubes create a percolating network for efficient electron transport. Poly-α-hydroxy ester binders dramatically boost strain tolerance and adhesion, mitigating pulverization and preserving electrical contact during cycling. These synergistic design elements deliver reversible capacities above 1,000 mAh/g with superior cyclability and rate performance.
Description
The technology employs a high-energy mechanochemical reduction of silicon monoxide (SiO) with boron under inert, dry or wet conditions to yield nanocrystalline silicon and B₂O₃. The nascent silicon is then co-milled with graphite and a polymeric precursor such as polyacrylonitrile to prevent SiC formation and achieve a uniform Si–graphite dispersion. Multiwalled carbon nanotubes are introduced via ultrasonication, and the mixture is pyrolyzed in ultra-high-purity argon at 500–1,000 °C, forming an amorphous carbon interface around silicon. Poly-α-hydroxy ester binders (e.g., PCL, PLA, PLGA) soluble in aprotic solvents replace PVDF to accommodate silicon’s volume changes. Final electrodes are cast onto copper or nickel substrates and characterized by XRD, TEM/SEM, FTIR, and electrochemical cycling and impedance tests.
Applications
EV battery anodes
Consumer electronics batteries
Grid energy storage anodes
Wearable device batteries
Aerospace battery anodes
Advantages
High reversible capacity (>1000 mAh/g) for increased energy density
Enhanced cycle stability through uniform Si–graphite dispersion and amorphous carbon interface
Mitigated silicon volume expansion using poly-α-hydroxy ester binders with superior strain tolerance
Improved electronic conductivity and mechanical integrity from multi-walled carbon nanotubes
Controlled electrolyte access and reduced irreversible capacity loss via B₂O₃ modulation
Scalable mechanochemical process operable under dry or wet conditions
Versatile electrode fabrication on copper or nickel substrates using dip, spray, or slurry coating
IP Status
https://patents.google.com/patent/US8658062B2
