Diatoms are unicellular #microalgae with cell walls composed of transparent, opaline silica.
Cost-efficient #diatom-based batteries, like other silicon-based anode technologies, offer several environmental benefits compared to traditional #lithium-ion batteries, and potentially becoming #mainstream #batteries.
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Processing diatoms for battery use involves several steps to transform their silica structures into effective anode materials for lithium-ion batteries. Here’s an overview of the process:
1. **Harvesting Diatoms**: After cultivating diatoms, they are harvested using methods like filtration, centrifugation, or sedimentation to separate them from the growth medium¹.
2. **Cleaning and Purification**: The harvested diatoms are cleaned to remove organic matter and impurities. This can involve washing with water and chemical treatments to ensure the silica frustules are pure¹.
3. **Silica Extraction**: The silica from the diatom frustules is extracted. This can be done through thermal processing, where the diatoms are heated to high temperatures to remove any remaining organic material, leaving behind pure silica².
4. **Reduction to Silicon**: The silica (SiO₂) is then reduced to silicon (Si) through chemical processes. One common method involves using magnesium or other reducing agents to convert silica into silicon².
5. **Nanostructuring**: The silicon derived from diatoms is often nanostructured to enhance its electrochemical properties. This can involve grinding the silicon into nanoparticles or creating porous structures to increase the surface area³.
6. **Carbon Coating**: To improve the conductivity and stability of the silicon anode, a carbon coating is applied. This can be done through chemical vapor deposition or other coating techniques³.
7. **Electrode Fabrication**: The processed silicon is then mixed with conductive additives and binders to create a slurry. This slurry is coated onto a current collector (usually copper foil) and dried to form the anode material³.
8. **Battery Assembly**: The anode is assembled with the cathode, separator, and electrolyte to form a complete lithium-ion battery. The battery is then sealed and subjected to electrochemical testing to ensure it meets performance standards².
These steps leverage the unique properties of diatom silica, such as its high surface area and porous structure, to create efficient and high-capacity anode materials for batteries.
Source:
(1) Silica from diatom frustules as anode material for Li-ion batteries.
(2) Synthesis and Characterization of Lithium-Ion Based Diatom Batteries By.
(3) Nanostructured diatom earth SiO2 negative electrodes with superior .... https://lnkd.in/epRuAnj8.
(4) Diatoms Biomass as a Joint Source of Biosilica and Carbon for ... - MDPI. https://lnkd.in/ezQ_TfZp.
