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Abstract Lithium sulfur batteries have attracted significant attention owing to their remarkably high theoretical capacities and energy density for the potential next-generation energy storage system. Considerable efforts have been developed to improve the redox reversibility and suppress sulfur loss when maintaining their capacities. However, few strategies have enlightened to address shuttle issues via electric-field-responsive film. Here, we postulate a new strategy to create smart electric-field-responsive surface structure and design special molecular film with quaternary ammonium group. The responsive film bonded to carbon matrix can act as a switch to control the on-off of polysulfide channels. Meanwhile, the prepared carbon aerogel (CA) matrix presents highly cross-linked 3D framework, abundant hierarchical pore channels and high specific surface area. The results show the composite sulfur cathode with selective film exhibits outstanding high discharging capacities and long-term cycling stability. Specifically, the cathode with 61.6 wt% sulfur displays an initial specific capacity of 1307 mAh g−1 at 0.2C and maintains 84.0% after 100 cycles. The improved electrochemical performance may mainly benefit from the switch function of self-responsive film, effectively preventing polysulfides escaping from the cathode, suppressing shuttle effect and enhancing the utilization of sulfur. Furthermore, the adsorption calculation by the density functional theory (DFT) shows trapping role of beta-cyclodextrin quaternary ammonium (CDQA) to polysulfides. The DFT simulation further supports the confining and switching mechanism. [ABSTRACT FROM AUTHOR]

Cadmium-doped carbon aerogels were successfully prepared via a microtemplate inducing strategy and subsequent high temperature carbonization. The controlled synthesis technology forms spherical carbon aerogels with uniform and interconnected porous structures. The as-prepared materials display large specific surface area and excellent conductivity. The loaded sulfur composites as cathode materials exhibit high discharge capacity and excellent cycling performance. Particularly, the designed P2-Cd-CA/S electrode with 78.9 wt% sulfur presents an initial discharge capacity of 1318 mA h g−1 at 0.2C. And it delivers an initial discharge capacity of 1189 mA h g−1 at 0.5C and still maintains 871 mA h g−1 after 300 cycles. The enhanced performance is mainly ascribed to the synergistic effect of the inductive graphitization of a microtemplate (3,4,9,10-perylenetetracarboxylic dianhydride) and the stronger anchoring for polysulfides of evenly distributed cadmium. Furthermore, the first-principles theoretical calculations further support the strong adsorption between CdO and polysulfides and affirmatively reveal the immobilizing mechanism. [ABSTRACT FROM AUTHOR]

A cage‐type composite was successfully prepared by attaching p‐sulfonatocalix[4]arene to a porous activated carbon aerogel (ACA). The resulting composite showed a high specific surface area of 1620.7 m2 g−1 and a high sulfur loading of 2.5 mg cm−2. The calixarene is uniformly dispersed on the carbon spheres and efficiently captures polysulfides by interaction with the sulfonate groups. Meanwhile, the cross‐linked porous structure of the composite restricts the migration of polysulfides. The cathode delivers an outstanding electrochemical performance with an initial capacity of 1304.7 mAh g−1 at 0.2 C. Furthermore, it displays excellent long‐term cycling stability, maintaining 884.7 mAh g−1 after 300 cycles at 0.5 C. Density functional theory (DFT) adsorption calculations support the strong interaction between the calixarenes and polysulfides and reveal the capture mechanism. [ABSTRACT FROM AUTHOR]