Background

The next generation of green based materials for fuels, commodity chemicals, and materials is being led by the conversion of biomass based on their low-cost and availability. Biomass materials have advantages such as renewability, tunable physical characteristics dictated by the natural structures within the feedstock, and their similarity to commercial graphite based conductive materials. Methods used to incorporate transistion metals into the materials typically involve soaking the biomass in toxic metal salts – adding additional steps and resource expenditure. Additionally, dead biomass only allows for the sorption of one mode, preventing the localization into actively growing biomass. The use of crops and woody biomass is also hindered by the slow growth conditions (days to years).

Technology Overview

Inventors at the University of Colorado Boulder have developed a method to eliminate this limitation using a fast-growing, filamentous fungi, Neurospora crassa. Additionally, they are able to demonstrate control of the electrochemical properties of an electrode derived from the biomass through the manipulation of the biological growth conditions during the growth of the material, as opposed to post-growth modification. The chemical composition of the fungi can be modified by adjusting the concentrations of sodium nitrate and cobalt exposure in the pre-growth material, regulating the nitrogen assimilation and ultimately forming cobalt nanoparticles in the fungal structure (). In this way, the extent of the nitrogen-doping was controlled. Pyrolysis of the material was conducted at 800°C, and the 3-D microstructure was preserved from the parent material.

Stage of Development

Proof of concept

Benefits

High order structure
Rapid growth (<24 hr to create 1000x original mass)
Increased capacitance compared to electrodes derived from pre-grown biomass
Shaping characteristics of an electrode during growth of biotemplate
Reduction in polarization resistance and higher electrochemical stability

Applications

Synthesis of carbon anodes
Energy storage

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Growth of Fungal Electro-Chemical Materials