Selenium exhibits smaller volume expansion and much higher electrical conductivity compared with sulfur, which makes it considered as a potential cathode material. In order to improve electrochemical performance of potassium‐selenium (K−Se) batteries, we prepared porous carbon/Se (PC/Se) composite via carbonization, KOH activation and melt diffusion and synthesized a novel porous carbon/Se/graphene oxide (PC/Se/GO) composite with the Se content of ∼40 % via controlling the ionic strength of the solution as cathode material in the work. The combination of porous carbon structure and graphene can effectively relieve the volume expansion of selenium during the charge and discharge process, and provide excellent conductivity. The one‐step conversion without polyselenides between the PC/Se/GO composite and metal potassium further improves the capacity and cycling stability. Therefore, the PC/Se/GO delivers high discharge capacities of 426.3 and 316.8 mAh g⁻¹ in the 2nd and 150th cycles at 0.5 C. This work plays an important reference role for the exploration of advanced potassium‐selenium batteries.

中文翻译：

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基于硒的生物质碳和氧化石墨烯中钾硒电池的新型阴极

与硫相比，硒的体积膨胀小，导电率高，因此被认为是潜在的阴极材料。为了提高钾硒电池的电化学性能，我们通过碳化，KOH活化和熔融扩散制备了多孔碳/硒（PC / Se）复合材料，并合成了新型多孔碳/硒/氧化石墨烯（PC）。通过控制溶液中作为阴极材料的溶液的离子强度，使Se含量约为40％。多孔碳结构和石墨烯的结合可有效缓解硒在充放电过程中的体积膨胀，并提供出色的导电性。PC / Se / GO复合材料与金属钾之间的无聚硒化物的一步转化进一步提高了容量和循环稳定性。因此，PC / Se / GO具有426.3和316.8 mAh g的高放电容量在0.5 C的第二和第150循环中为^-1。这项工作对于探索高级钾硒电池具有重要的参考作用。