Wild Fungus Derived Carbon Fibers and Hybrids as Anodes for Lithium-Ion Batteries

We reported a facile synthesis of carbonaceous fibers directly from Tyromyces fissilis wild fungus through a controlled carbonization process. Electron micrograph observations revealed that as-prepared carbon fibers are composed of 40-60 mu m long solid and tubular fibers mimicking their natural texture. Raman spectroscopy and X-ray diffraction indicated that these carbon fibers are possessing disordered carbon structure with larger interlayer spacing (0.386 nm) than graphite (0.335 nm). These carbon fibers delivered specific reversible capacity of 340 mAh/g at C/10 rate and 300 mAh/g at C/5 rate. Electrochemical performance of as-prepared carbon fibers was further improved by uniform decoration of cobalt oxide particles via solid state thermal processing. CoO-carbon fiber hybrid anode delivered higher reversible capacity, 530 mAh/g at C/10 rate with only 10 mol % of CoO loading. This improvement is attributed to the synergistic effect, namely conductive network of cross-linked carbon fibers and facile electrochemical reaction with deposited monodispersed CoO nanoclusters. Cyclic voltammetry and electrochemical impedance spectroscopy on both carbon fiber and hybrid anodes were conducted to comprehend the lithiation and delithiation processes.