A bioinspired three-dimensional nanofibrous Cu-nanoparticle/SnO2/carbon composite as an anodic material for lithium-ion battery

To improve the stability and the reversibility of the SnO2-based anodic materials in lithium ion batteries, a new bioinspired nanostructured Cu-nanoparticle/SnO2/carbon (Cu-NP/SnO2/carbon) composite was fabricated by employing natural cellulose substance (e.g., commercial laboratory cellulose filter paper) as both scaffold and carbon source. The as-deposited SnO2-gel/cellulose composite was firstly calcined and carbonized in argon atmosphere, and the resulted nanofibrous SnO2/carbon composite was further uniformly decorated with the metallic Cu nanoparticles via a facile chemical reduction process using copper nitrate as the precursor. The nanocomposite was composed of SnO2-layer-coated carbon nanofibres with Cu nanoparticles immobilized on the surfaces. As an anode material for lithium-ion batteries, the three-dimensional porous structure of the nanocomposite inherited from the initial cellulose substance effectively buffered the large volume change during the cycling processes; moreover, the uniformly decorated Cu nanoparticles significantly facilitated the electron transport, as well as reversibly promoted catalytic decomposition of Li2O during delithiation process to enhance the reversible capacity of the electrode. Therefore, the Cu-NP/SnO2/carbon anodes exhibited an improved electrochemical performance compared with the nanofibrous SnO2/carbon material. For the composite with 24.6 wt% of the Cu content and the sizes of 5-10 nm of the Cu nanoparticles, it delivered a superior performance with the highest specific capacity of 797 mAh g(-1) after 120 charge/discharge cycles at a current density of 100 mA g(-1).