Silicon Nanofiber Paper Battery

Tech ID: 32652 / UC Case 2014-810-0

Patent Status

Country Type Number Dated Case
United States Of America Issued Patent 10,211,449 02/19/2019 2014-810

Full Description


High theoretical capacity, availability abundance, non-toxicity and environmental benignity make Silicon (Si) the preferred choice of anode for next generation Lithium-ion batteries. Large volumetric expansion (~300%), achievement of Si nanostructures (characteristic dimension below 150 nm) and pragmatic fabrication process are critical obstacles to overcome to build Lithium-Silicon batteries for real world applications. Electrospinning of polymers, dissolved in organic solvents along with active material such as Si, is a feasible fabrication process. However, current electrospinning methods:

  • Require lengthy, thermal oxidative stabilization and carbonization steps.
  • Build electrodes with reduced capacity because the weight percentage of active material can be less than 50%.

Current Invention

Prof. Cengiz Ozkan and his research team have developed a patented, binderless, freestanding, Silicon Nanofiber (SiNF) paper with Si weight percentage in excess of 80%. SiNF paper is synthesized via magnesiothermic reduction of SiO2 nanofiber (SiO2NF) paper which is produced by an in situ acid-catalyzed polymerization of tetraethyl orthosilicate (TEOS) in flight. To enhance the surface conductivity of the electrode, a 4 nm carbon coating is applied to the SiNF paper.

Schematic illustration

Schematic illustration of the electrospinning and the subsequent reduction process.

Cycling data

Cycling data for carbon-coated SiNF compared to uncoated SiNF at C/10 rate.


The novel aspects and benefits of their invention are:

  • Existence of a 1-2 nm thickness, native SiO2 shell on all the Silicon nanoparticles (SiNP) serves to mitigate volume expansion effects during lithiation.
  • The diameter of the SiNPs are 8 – 25 nm, well below the critical dimension.
  • Reduced bulk diffusion length for Lithium.
  • Excellent electrochemical stability and high degree of scalability.
  • No carbon black, metallic current collectors or polymer binders.
  • Magnesiothermic reduction process requires lower operating temperatures (700 deg. C).

Suggested uses

  • Lithium-ion and Lithium-Silicon batteries


The team fabricated 2032 type coin cells with SiNF electrodes. After 650 cycles, the SiNF electrodes deliver a reversible capacity of 802 mAh/gram and a coulombic efficiency of 99.9%.

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Other Information


Lithium ion battery, Lithium Silicon battery, Silicon Nanofiber, Paper battery, Renewable energy, Magnesiothermic reduction, Electric Vehicles

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