硫化聚丙烯腈凝胶的制备及其锂硫电池性能

Preparation and lithium sulfur battery performance of sulfurized polyacrylonitrile gel

为了提高硫化聚丙烯腈(SPAN)正极材料的电化学性能,以二甲基亚砜为溶剂,以去离子水为非溶剂,采用热致相分离法制备了聚丙烯腈凝胶(PAN)_g,然后引入水合肼使PANg的分子链间发生N—N交联,制备出化学交联的聚丙烯腈凝胶(PAN_(g+N)),最终通过高温载硫法制得了硫化聚丙烯腈凝胶(SPAN_(g+N))。利用SEM、TEM、FTIR、XRD等方法研究了材料的结构和物相特征。结果表明:交联结构的SPAN_(g+N)具有高度互联的三维网络结构,结构稳定性及电化学性能均得到显著提高。在0.5 C的电流密度时,首圈放电比容量为1 219.8 mA·h/g,循环100圈后的比容量为1 000.6 mA·h/g,容量保持率达到82.03%,平均每圈衰减率为0.18%。

In order to improve the electrochemical performances of sulfurized polyacrylonitrile(SPAN)cathode material,polyacrylonitrile gel(dennoted as PANg)was prepared via thermally induced phase separation method using dimethyl sulfoxide as the solvent and deionized water as non-solvent.The introduction of hydrazine hydrate caused N—N crosslinking between the molecular chains of PANg to produce a chemically crosslinked polyacrylonitrile gel(dennoted as PAN_(g+N)).The vulcanized polyacrylonitrile gel(dennoted as SPAN_(g+N))was obtained by high-temperature sulfurization method.The structure and phase characteristics of materials were studied by SEM,TEM,FTIR,XRD and other methods.The results show that SPAN_(g+N) with crosslinked structure has a highly interconnected three-dimensional network structure with significantly improved structural stability and electrochemical properties.At a current density of 0.5 C,the discharge specific capacity of the material is 1219.8 mA·h/g at the first turn,and it can still maintain 1000.6 mA·h/g after 100 cycles,with a capacity retention rate of 82.03%and an average attenuation of 0.18%per cycle.