Silica materials from diatom frustules, with porous architecture, large surface area, and low costs are promising candidates for metal oxide loading, which could be used as supercapacitor electrode materials. Diatom silica would contribute to the electrochemical cell performance by double-layer capacitance in addition to the pseudocapacitance brought by the iron oxides. The cultured diatom was compared with diatomaceous earth, and it showed higher capacitance regarding surface area, pore volume, specific capacitance and also found more suitable for metal oxide loading. The FeOx coating of diatom biosilica prepared with hydrolysis and metathesis reaction of FeCl3 in alkaline solution. This reaction allowed the coating of FeOx onto both internal and the external surface of diatom frustules. Results showed that a 5% loading of FeOx on cultured diatom significantly enhanced performance to 13.7 F g-1, which was 90% higher compared with cultured diatom only. Flexible electrodes were also fabricated using the resulted CD-FeOx composite. The synthesis and treatment method is universal and readily to be applied into other diatom-metal oxide composite production especially for electrochemical applications.

Biosilica from cultured diatom and its composite with Iron oxide for supercapacitors electrodes

2019 Spring National Meeting

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