The rational design of cathode materials for lithium–selenium (Li–Se) batteries is essential to achieve high-performance electrochemical properties with long cycle life and excellent rate capability. In this paper, novel porous carbon nanofibers with bimodal pores (micro/meso), as efficient cathode hosts for Li–Se batteries, were successfully synthesized by carbonization of electrospun zeolitic imidazole framework-8/polyacrylonitrile (ZIF-8/PAN) nanofibers and further chemical activation. Mesopores originated from carbonization of ZIF-8 embedded in the carbon nanofiber, and micropores were further introduced via KOH activation. During the activation step, micropores were introduced to the ZIF-8-derived meso porous carbon cages and within the carbon nanofibers, resulting in the formation of bimodal porous carbon nanofibers with enlarged pore volumes. Owing to their mesopores for easy access of electrolyte and high utilization of chain-like selenium with low-range ordering within the micropore, the selenium-loaded bimodal porous carbon nanofibers exhibited high discharge capacity and superb rate performance. The discharge capacities of the nanofibers at the 2^nd and 300^th cycle at a current density of 0.5C were 742 and 588 mA h g⁻¹, respectively. The capacity retention calculated from the 2^nd cycle was 79.2%. In addition, a discharge capacity of 568 mA h g⁻¹ was obtained at an extremely high current density of 10.0C.

中文翻译：

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硒-渗透的金属-有机骨架衍生的多孔碳纳米纤维包括互连双峰孔隙锂硒电池具有高容量和倍率性能†

锂-硒（Li-Se）电池正极材料的合理设计对于实现高性能电化学性能，长循环寿命和出色的倍率能力至关重要。在本文中，通过电纺沸石咪唑骨架8 /聚丙烯腈（ZIF-8 / PAN）纳米纤维的碳化，成功地合成了具有双峰孔（micro / meso）的新型多孔碳纳米纤维，作为锂硒电池的高效阴极主体。进一步的化学活化。中孔源自嵌入在碳纳米纤维中的ZIF-8的碳化，微孔通过KOH活化。在活化步骤中，将微孔引入到ZIF-8衍生的介孔碳笼中和碳纳米纤维中，导致形成具有增大的孔体积的双峰多孔碳纳米纤维。由于它们的中孔易于进入电解质并且在微孔内以低范围有序地高利用链状硒，因此，硒负载的双峰多孔碳纳米纤维表现出高放电容量和出色的速率性能。纳米纤维在^第二循环和^第三循环中在0.5C的电流密度下的放电容量分别为742和588mA hg ^-1。根据^第二次计算的容量保留周期为79.2％。另外，在10.0℃的极高电流密度下获得了568mA hg ^-1的放电容量。