Rose pollens as sustainable biotemplates for porous SiOC microellipsoids with enhanced lithium storage performance

Abstract Exploring of high specific capacity, long cycling stability and high rate capability anode materials with low cost and environmentally benign is closely bound up with the breakthrough of high energy density lithium ion batteries. Inspired by uniform geometries and elaborate morphologies of natural rose pollens, a series of porous SiOC microellipsoids are fabricated by a novel supercritical CO2 fluid assisted carbonization method using rose pollen as biotemplate and carbon source. The high permeability, superior diffusivity and excellent dissolving capability of supercritical CO2 fluid guarantees the efficient mass transfer, leading to the homogeneous elemental distributions in precursor and final product of SiOC. Interestingly, the content of free carbon phase, SiO2C2, SiO3C and SiO4 units in SiOC can be adjusted by varying the calcination temperature. The relationship between mixed SiCxO4-x units and electrochemical performance is systematically investigated. The results demonstrate that SiOC-600 with high content of SiO2C2 and SiO3C units delivers a satisfactory reversible capacity (415.1 mA h g−1 at 0.1 A g−1), a prolonged cycling life (351.3 mA h g−1 after 200 cycles) and enhanced rate capability (175.2 mA h g−1 at 2 A g−1).