Porous Ge@C materials via twin polymerization of germanium(ii) salicyl alcoholates for Li-ion batteries?

Journal of Materials Chemistry A Pub Date: 2016-01-22 DOI: 10.1039/C5TA09891B

Abstract

The germylenes, germanium(II) 2-(oxidomethyl)phenolate (1), germanium(II) 4-methyl-2-(oxidomethyl)phenolate (2) and germanium(II) 4-bromo-2-(oxidomethyl)phenolate (3) were synthesized and their thermally induced twin polymerization to give organic–inorganic hybrid materials was studied. The compounds 1–3 form oligomers including dimers, trimers and tetramers as a result of intermolecular coordination of the benzylic oxygen atom to germanium. The structural motifs were studied by single crystal X-ray diffraction analysis and DFT-D calculations. Thermally induced twin polymerization of these germylenes gave hybrid materials based on germanium-containing phenolic resins. Carbonization of these resins under reductive conditions resulted in porous materials that are composed of germanium and carbon (Ge@C materials), while oxidation with air provided non-porous germanium dioxide. The porous Ge@C materials were tested as potential anode materials for rechargeable Li-ion batteries. Reversible capacities of 540 mA h g?1 were obtained at a current density of 346 mA g?1 without apparent fading for 100 cycles, which demonstrates that germanium is well accessible in the hybrid material.

Graphical abstract: Porous Ge@C materials via twin polymerization of germanium(ii) salicyl alcoholates for Li-ion batteries
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