Hybrid Ascharite/Reduced Graphene Oxide with Polysulfide Adsorption Host for Advanced Lithium–Sulfur Batteries

Abstract

Balancing the adsorption of lithium-polysulfide intermediates on polar host material surfaces and the effect of their electronic conductivity in the subsequent oxidation and reduction kinetics of electrochemical reactions is necessary and remains a challenge. Herein, we have evaluated the role of polarity and conductivity in preparing a series of ascharite/reduced graphene oxide (RGO) aerogels by dispersing strong polar ascharite nanowires of varying mass into the conductive RGO matrix. When severed as Li–S battery cathodes, the optimized S@ascharite/RGO cathode with a sulfur content of 73.8 wt % demonstrates excellent rate performance and cycle stability accompanied by a high-capacity retention for 500 cycles at 1.0 C. Interesting advantages including the enhanced adsorption ability by the formation of the Mg–S and Li bonds, the continuous and quick electron/ion transportations assembled conductive RGO framework, and the effective deposition of Li2S are combined in the ascharite/RGO aerogel hosts. The electrochemical results further demonstrate that the polarity of ascharite components for the S cathode plays a dominant role in the improvement of electrochemical performance, but the absence of a conductive substrate leads to serious capacity attenuation, especially the rate performance. The balanced design protocol provides a universal method for the synthesis of multiple S hosts for high-performance LSBs.

Design and synthesis of few-layer molybdenum oxide selenide encapsulated in a 3D interconnected nitrogen-doped carbon anode toward high-performance sodium storage

“…In the high-resolution spectra of C 1s (Fig. 3b), three peaks at 284.8, 286.3, and 289.3 eV correspond to the binding energy of C–C/CC, C–O/C–N, and OC–O groups, 35–37 respectively. In the high-resolution spectra of Mo 3d (Fig.…”

Fabricating a high-performance anode by coating a carbon layer on a yolk–shell bimetallic selenide microsphere for enhanced lithium storage

“…To overcome the bottleneck of TMSe anodes for LIBs, researchers are exploring new strategies to optimize their electrochemical performances via the modification of electrode materials and phase engineering. In recent studies, strategies mainly including the design of nano-processing, morphological and phase control, and the hybridization of active materials with conductive buffering matrix 12,13 are usually adopted. For example, the yolk–shell structure can not only expose more active sites, increasing the contact area between the electrode material and the electrolyte, but also buffer the impact of volume changes on the electrochemical performance.…”