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Electrospinning is a common approach for the fabrication of composite carbon nanofibers (CNFs) used as cathodes in lithium-oxygen batteries (LOBs). However, the addition of a salt precursor in the synthetic procedure makes a strong impact on the final morphology and structure of composites, directly affecting the battery performance. Herein, 3D hierarchical porous CNFs with different loading amounts of metallic Co are prepared in situ by the electrospinning method combined with a thermal annealing process. Notably, we find that with the overloading of metallic Co, the resultant hybrid CNFs become rather fragile, resulting in a discontinuous nanorod structure. In contrast, an optimal addition of the Co precursor is found to create a continuous and integrated porous structure within the CNFs, leading to the highest surface area. The free-standing Co/CNFs films can not only supply a high number of active sites and facilitate reactant diffusion but also provide abundant Li 2 O 2 storage that can avoid binder-induced side reactions. Benefiting from the structural advantages and superior catalytic performance of Co, the resultant battery achieves a large capacity, outstanding rate capability and a good cycling stability and exhibits great potential for application in LOBs. [ABSTRACT FROM AUTHOR]

Composition carbon materials with metal chalcogenides for the application of energy storage have attracted great attention due to the combination of good conductivity with high capacity. In this work, ultrasmall few-/single-layered WS 2 @nitrogen-doped carbon nanofibers(WS 2 @NCNFs) are successfully synthesized via electrospinning and annealing. The WS 2 @NCNFs cathode exhibits a discharge capacity of 314.07 m A h g − 1 and maintains 195.81 m A h g − 1 after 100 cycles at 100 m A g − 1 , which is superior to that of the bulk WS 2 cathode. The special composite nanostructure endows the WS 2 @NCNFs cathode with outstanding aluminum storage performances, which may provide new insight for realizing more attractive two-dimensional layered cathode materials for rechargeable aluminum batteries. Image 1 • Single-/few-layered WS 2 embedded in NCNFs is synthesized. • WS 2 @NCNFs exhibits outstanding performance in RABs. • Both pseudocapacitive effect and battery behavior contribute to capacity. • Al3+ can intercalate into two different positions in WS 2. [ABSTRACT FROM AUTHOR]