Co-introduction Of CuSO₄ And Zinc N-ethyl-n-phenyldithiocarbamate For Preparing Vulcanized Polyacrylonitrile Cathode Materials

In order to improve the electrochemical performance of vulcanized polyacrylonitrile（SPAN）cathodes,the vulcanization reaction of polyacrylonitrile（PAN）was investigated in this work in an attempt to increase the elemental sulfur content in SPAN materials.Three aspects of research work have been carried out:（1）The introduction of cyclization reaction accelerators（nickel nitrate（Ni（NO₃）₂）,cobalt nitrate（Co（NO₃）₂）or copper sulfate（Cu SO₄））into the PAN vulcanization reaction system was investigated to improve the structural regularity and increase the sulfur content in the products by promoting the cyclization reaction of PAN.And it turned out that the introduction of Cu SO₄could effectively increase the sulfur content of the product to 52.39 wt%,and form Cu S in the structure.Thus,the modified SPAN cathode delivered a high initial discharge capacity of 863.7 m Ah g^-1 at 0.2 C(1 C=600 m Ah g^-1),and maintained a high capacity retention rate of 70%at 100 cycles.（2）The effects of vulcanization reaction accelerators—Zinc N-ethyl-N-phenyldithiocarbamate（ZDB）and dibenzothiazole disulfide（MBT）on the vulcanization of PAN were investigated.Vulcanization accelerator can promote the reaction between S and PAN and increase the sulfur content of the product by providing more reaction active sites.The results showed that ZDB has a good promotion effect on the PAN vulcanization reaction,and the sulfur content of SPAN using ZDB as the vulcanization accelerator was enchaned to54.13 wt%.The modified SPAN cathode could output a high initial discharge capacity of 829.0 m Ah g^-1 at 0.2 C with a capacity retention rate of 90%after50 cycles.（3）The reaction of S and PAN was further improved by adding the composite of Cu SO₄ and ZDB into the reaction system.The combined effect of the two was found,which proved that it could improve the cycle stability of lithium battery with the product as positive active material.At 0.2 C,the modified SPAN displayed a high initial discharge capacity of 805.4m Ah g^-1,and maintained a high discharge capacity of 600.8m Ah g^-1 after 100 cycles with the outstanding capacity retention rate of 92%.The combined effect of cyclization accelerators and vulcanization accelerators can improve both sulfur content and discharge capacity,as well as the cycle stability,providing a basis for the development of high specific energy batteries.