Synthesis Of Tin-based Anode Materials For Lithium Ion Batteries With Improved Reversible Capacity

Lithium-ion batteries (LIBs), currently as ubiquitous power sources forconsumer electronics, are now considered for electric or hybrid vehicles. To improvethe energy density and cycling life capacity of battery system, a great deal of effortshas been made to take a further step in superior performance electrode materials. Asone of the most promising anode materials, tin-based anode material has attractedextensive attention as a potential substitute for carbon anode (theoretical capacity372mAh g-1) because of its higher theoretical capacity. However, the practical applicationof tin-based anode material is hindered by huge volume change of300%during Li+insertion/extraction process, which leads to very rapid capacity decay andpulverization of electrodes. In this thesis, some work has been done to improve theelectrochemical properties of tin-based anode material for lithium ion batteries. Thefollowing two aspects were mainly studied.1. a facile bio-synthesis strategy was proposed to prepare biomorphicSnO2/C composites on large-scale with cotton as template and biocarbon source.By varying sintering temperature, the content of carbon in the composites, which hadgreat effects on their electrochemical performances, could be easily adjusted. Thebiomorphic SnO2composites prepared at300oC exhibited a reversible capacity of530mAh g-1after100cycles at a current density of100mA g-1.2. monodisperse and uniform porous Zn-Sn-O cubes were successfullysynthesized by a template-free aqueous solution method combined withsubsequent calcination of ZnSn(OH6) crystallites in air. The calcinating temperature has great effects on the crystalinity, morphology and structure of theobtained Zn-Sn-O cubes. The as-prepared porous Zn-Sn-O cubes prepared at600oCmainfested meaningfuly improved Li storage performance, with a reversible capacityof about700mAh g-1up to50cycles at a current density of200mA g-1.3. ZnSnO3nanoboxes were synthesized by etching and ZnSnO3-PPy weresynthesized by in situ oxidative chemical polymerization. The as-prepared ZnSnO3nanoboxes and ZnSnO3-PPy both exhibited a reversible capacity around500mAh g-1after50cycles at a current density of200mA g-1.