【摘 要】
：
Potassium-selenium(K-Se)batteries have attracted more and more attention because of their high the-oretical specific capacity and natural abundance of K resources.However,dissolution of polyselenides,large volume expansion during cycling and low utilizati
【机 构】
：
Hefei National Laboratory for Physical Sciences at the Microscale,Department of Materials Science an
论文部分内容阅读
Potassium-selenium(K-Se)batteries have attracted more and more attention because of their high the-oretical specific capacity and natural abundance of K resources.However,dissolution of polyselenides,large volume expansion during cycling and low utilization of Se remain great challenges,leading to poor rate capability and cycle life.Herein,N/O dual-doped carbon nanofibers with interconnected micro/me-sopores(MMCFs)are designed as hosts to manipulate Se molecular configuration for advanced flexible K-Se batteries.The micropores play a role in confining small Se molecule(Se2-3),which could inhibit the formation of polyselenides and work as physical barrier to stabilize the cycle performance.While the mesopores can confine long-chain Se(Se4-7),promising sufficient Se loading and contributing to higher discharge voltage of the whole Se@MMCFs composite.The N/O co-doping and the 3D interpenetrating nanostructure improve electrical conductivity and keep the structure integrity after cycling.The obtained Se2-3/Se4-7@MMCFs electrode exhibits an unprecedented cycle life(395 mA h g-1 at 1 A g-1 after 2000 cycles)and high specific energy density(400 Wh kg-1,nearly twice the specific energy density of the Se2-3@MMCFs).This study offers a rational design for the realization of a high energy density and long cycle life chalcogen cathode for energy storage.
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