Study On Solvthermal Synthesis And Li-storage Preperties Of Antimony-based Materials

The graphite anode has a relatively low theoretical specific capacity （372mAh/g）,thereby restricting its future applications. So, it is very important to develop alternativeanode materials with higer specific capacity and bettery cycling durability for the newgeneration Li-ion batteries. Sb has a theoretical capacity of660mAh/g, which is almosttwice that of graphite. However, the big problem accompanying with the above alloyingreaction is the drastic volume expansion after lithiation, thus usually resulting in a poorcycle performance. It is commonly agreed now that using a nano-structured electrode or amulti-phase material can greatly relieve the volume expansion associated with the alloyingreaction. In this paper, antimony-based composite materials （Sb₂S₃, Sb₂S₃@C andSb4O5Cl2/rGO/C composites） were prepared by a simple solvothermal treatmen, theirmorphology, microstructure and electrochemical performances of intercalation wereinvestigated.（1） Sb₂S₃@C composite nanorods were synthesized successfully by a facile ethanolsolvothermal treatment, when L-cys.HCl and SbCl3mole ratio is3:1,180oC keep8h. Theas-synthesized Sb₂S₃@C composite was found to display the highest lithiation anddelithiation during the first cycle,823/1165mAh/g, with the initial Coulombic efficiency of70.6%, reversible specific capacity is623mAh/g after30cycles at a current density of100mA/g,75.7%capacity retention, and reversible specific capacity stay above400mAh/g ata current density of500mA/g. In addition, carbon-coated materials can improve Sb₂S₃electrochemical lithium storage properties of electrode materials, coated carbon designcontent for5wt.%of the Sb₂S₃@C composite material has the best electrochemicalproperties at a current density of100mA/g, display the highest reversible specificcapacity（1084mAh/g）, excellent long performance （after30cycles capacity is960mAh/g,88.5%capacity retention） and the excellent rate of properties （capacity is1019mAh/g at acurrent density of500mA/g）. Sb₂S₃-based electrode material of ultra-high capacity isascribed to part of Sb₂S₃reversible decomposition and reconstruction duringelectrochemical lithium storage, this also confirmed the nanorods structure promoted theSb₂S₃decomposition/reconstruction on electrochemical reversibility during the chargingand discharging process, thus improve the initial coulombic efficiency and electrode specific capacity; Carbon-coated materials can not only improve the electrical conductivityof Sb₂S₃particles and relieve effectively volume change during the charging anddischarging process and disulfide dissolved in the electrolyte, but also promotereconstruction of Sb₂S₃and Li2S to S degree of reversible electrochemical reaction, thusimprove the reversible specific capacity composite material, performance and cycleperformance.（2） A Sb4O5Cl2/rGO/C composites was prepared by a simple solvothermal treatmentand tested as an anode material for lithium-ion batteries for the first time in this study. Thepreparatory experimental results showed that the as-prepared Sb4O5Cl2/RGO/C compositecould deliver a reversible capacity of636mAh/g for the first cycle, and moreover a highreversible capacity of334mAh/g could remain even after60cycles.