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 °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.