A novel type of one-dimensional organic selenium-containing fiber with superior performance for lithium-selenium and sodium-selenium batteries

A novel type of organic selenide fiber composed of carbonized polyacrylonitrile/selenium (CPAN/Se) has been synthesized by heating polyacrylonitrile-selenium (PAN-Se) fibers via the electrospinning technique at 600 degrees C. The Se molecules are confined by N-containing carbon ring structures in the form of energy-storing selenium side chains in the carbonized PAN matrix. This unique stable chemical structure with a conductive carbon skeleton connected to the selenium side chains and excellent mechanical stability can allow CPAN/Se composite cathodes to be charged and discharged in a low-cost carbonate-based electrolyte with excellent long cycle stability and quite good rate performance. The superior electrochemical performance of CPAN/Se electrodes is demonstrated in both lithium-ion and sodium-ion batteries, where they have delivered a high capacity of nearly 600 mA h g(-1) for 500 cycles in lithium-selenium (Li-Se) batteries and 410 mA h g(-1) for 300 cycles in sodium-selenium (Na-Se) batteries at 0.3 C, respectively.