Fe3O4/rice husk-based maco-/mesoporous carbon bone nanocomposite as superior high-rate anode for lithium ion battery

Rice husks (RHs), a kind of biowastes, are firstly hydrothermally pretreated by HCl aqueous solution to achieve promising macropores, facilitating subsequently impregnating ferric nitrate and urea aqueous solution, the precursor of Fe3O4 nanoparticles. A Fe3O4/rice husk-based maco-/mesoporous carbon bone nanocomposite is finally prepared by the high-temperature hydrothermal treatment of the precursor-impregnated pretreated RHs at 600 A degrees C followed by NaOH aqueous solution treatment for dissolving silica and producing mesopores. The macro-/mesopores are able to provide rapid lithium ion-transferring channels and accommodate the volumetric changes of Fe3O4 nanoparticles during cycling as well. Besides, the macro-/mesoporous carbon bone can offer rapid electron-transferring channels through directly fluxing electrons between Fe3O4 nanoparticles and carbon bone. As a result, this nanocomposite delivers a high initial reversible capacity of 918 mAh g(-1) at 0.2 A g(-1) and a reversible capacity of 681 mAh g(-1) remained after 200 cycles at 1.0 A g(-1). The reversible capacities at high current densities of 5.0 and 10.0 A g(-1) still remain at high values of 463 and 221 mAh g(-1), respectively.