Diatom Frustules Decorated with Co Nanoparticles for the Advanced Anode of Li‐Ion Batteries

Abstract

Silica is regarded as a promising anode material for lithium‐ion batteries (LIBs) because of its high theoretical capacity. However, large volume variation and poor electrical conductivity are limiting factors for the development of SiO2 anode materials. To solve this problem, combining SiO2 with a conductive phase and designing hollow porous structures are effective ways. In this work, The Co(II)‐EDTA chelate on the surface of diatom biosilica (DBS) frustules and obtained DBS@C‐Co composites decorated with Co nanoparticles by calcination without a reducing atmosphere is first precipitated. The unique three‐dimensional structure of diatom frustules provides enough space for the volume change of silica during lithiation/delithiation. Co nanoparticles effectively improve the electrical conductivity and electrochemical activity of silica. Through the synergistic effect of the hollow porous structure, carbon layer and Co nanoparticles, the DBS@C‐Co‐60 composite delivers a high reversible capacity of >620 mAh g−1 at 100 mA g−1 after 270 cycles. This study provides a new method for the synthesis of metal/silica composites and an opportunity for the development of natural resources as advanced active materials for LIBs.

Species-Dependent Nanostructured Diatom-SiO2 Anodes: A Sustainable Option for Optimizing Electrode Performance

“…Results showed a reversible specific capacity of about 1000 mAh g −1 at 200 mA g −1 after 150 cycles when frustules were carbon-coated with their original biomass, while non-coated frustules reported a reversible capacity of below 400 mAh g −1 . In an effort to improve the electrical conductivity of diatom-SiO 2 anodes, Chen et al 51 used frustules from cultured Navicula to fabricate SiO 2 /C composites decorated with different amounts of cobalt, showing a capacity increment from 280 to 515 mAh g −1 for SiO 2 /C and SiO 2 /C-Co-60, respectively, after 100 cycles at 100 mA g −1 .…”