Smart hybridization of active materials into tailored electrode structure is highly important for developing advanced electrochemical energy storage devices. With the help of sandwiched design, herein a powerful strategy is developed to fabricate three-layer sandwiched composite core/shell arrays via combined hydrothermal and polymerization approaches. In such a unique architecture, wrinkled MoSe 2 nanosheets are sandwiched by vertical graphene (VG) core and N-doped carbon (N-C) shell forming sandwiched core/shell arrays. Interesting advantages including high electrical conductivity, strong mechanical stability, and large porosity are combined in the self-supported VG/MoSe 2 /N-C sandwiched arrays. As a preliminary test, the sodium ion storage properties of VG/MoSe 2 /N-C sandwiched arrays are characterized and demonstrated with high capacity (540 mA h g −1 ), enhanced high rate capability, and long-term cycling stability (298 mA h g −1 at 2.0 A g −1 after 1000 cycles). The sandwiched core/shell structure plays positive roles in the enhancement of electrochemical performances due to dual conductive carbon networks, good volume accommodation, and highly porous structure with fast ion diffusion. The directional electrode design protocol provides a general method for synthesis of high-performance ternary core/shell electrodes.

No abstract

Lithium-sulfur batteries (LSBs) are considered to be one of the most promising alternatives to the current lithium ion batteries (LIBs) to meet the increasing demand of energy storage due to their high energy density, natural abundance, low cost and environmental-friendliness. Despite great success, LSBs are still suffering from several problems including undermined capacity arising from low utilization of sulfur, unsatisfactory rate performance and poor cycling life due to shuttle effect of polysulfides and poor electrical conductivity of sulfur. Under such circumstances, design/fabrication of porous carbon-sulfur composite cathodes is regarded as an effective solution to overcome the above problems. In this review, we summarize different synthetic methods of porous carbon hosts and corresponding integration ways of carbon-sulfur cathodes. We also address the pore formation mechanism of porous carbon hosts. The pore size effect on electrochemical performance is highlighted and compared. The enhanced mechanism of porous carbon host on the sulfur cathode is systematically reviewed and revealed. Finally, we demonstrate the combination of porous carbon hosts and high-profile solid-state electrolytes nowadays, and discuss the challenges to realize large-scale commercial application of porous carbon-sulfur cathodes and propose their developing trend in the future.

Pomegranate-structured Si/C mesoporous microspheres are fabricated by a facile one-step hydrothermal method with high cycling stability and superior rate capacity.