A three-dimensional fibrous tungsten-oxide/carbon composite derived from natural cellulose substance as an anodic material for lithium-ion batteries

To meet the ever-growing demands over electrochemical energy storage, tungsten trioxide (WO3) has aroused substantial attention as a promising anodic material for lithium-ion batteries due to its high theoretical capacity, abundant earth storage, and eco-friendliness. However, developing high-performance WO3-based electrodes is hampered by its restrictive conductivity and tremendous structural as well as the volumetric changes during the charge/discharge processes. Herein, a novel bio-inspired nanofibrous WO3/carbon composite was synthesized via a facile hydrothermal method employing pre-carbonized cellulose substrate (e.g., ordinary filter paper) as both the structural scaffold and the carbon source. The urchin-like WO3 microspheres with diameters of 3–6 μm assembled by nanorods were uniformly anchored on the surfaces of the cellulose-derived carbon fibers. The three-dimensional network structure of the composite was beneficial in alleviating the volume expansion of WO3 nanorods and enhanced the charge-transport kinetics of the electroactive materials. The composite with an optimized content of WO3 (26.36 wt%) exhibited superior lithium storage properties with an initial discharge capacity of 1470 mAh g−1 and an extraordinary long-term cycling performance of 682 mAh g−1 capacity retention after 300 cycles at 100 mA g−1. Furthermore, cyclic voltammetry, ex-situ XRD, and SEM measurements for mechanism studies were carried out to yield deeper insights into the synergism in the WO3/carbon electrodes, revealing the predominance of reversible pseudocapacitive intercalation of lithium-ions during the electrochemical reaction inside the WO3/carbon anode.