Effective Ways to Stabilize Polysulfide Ions for High‐Capacity Li−S Batteries Based on Organic Chalcogenide Catholytes

Abstract

Given the great promise of lithium-sulfur (LiÀ S) batteries as next-generation high-capacity energy storage devices, this feature article investigated critical parameters of the cathode, such as pretreatment of elemental sulfur (sublimed, polymerized, and crystallized), size of sulfur particles (19 vs. 35 μm) and aptness of current collector (aluminium vs. carbon paper). At the same time it also demonstrated the applicability of polychalcogenide-based catholytes (e. g., diphenyl disulfide and diselenide) that exhibited a record specific capacity (3000 mAh g À 1 at a C/5 rate) and an energy density of 1853 Wh Kg À 1 . From tweaking the sulfur nature in the cathode, where small-sized polymerized sulfur was found to promote the carbon-sulfur bond on the surface of carbon nanotubes, to trapping the polysulfide ions to formulate organochalcogenidebased catholytes, our study provided fundamental insights into key battery performance parameters as well as sulfur-polysulfide electrochemistry, inspiring future designs of such battery systems and more.

Lithium‐Ion Batteries Containing Surfactants for the Protection of Graphite Anode against the Passivation Layer Byproducts

“…The low potential region (i. e., 0.4-1.0 V vs. Li/ Li +) of the CV denotes the SEI layer formation. [29] A shoulder is evident around 0.9 V vs. Li/Li + for all electrolytes, followed by a pronounced peak assigned to the irreversible decomposition of electrolyte (initiated by the EC polymerization) and SEI formation as described largely in literature. [30] The potential of this peak (between 0.69 and 0.71 V vs. Li/Li +) is not influenced by the presence or the nature of the surfactant.…”

Characterization of Manganese Acetate Hydrate Solutions and Their Potential Use for Energy Storage Applications

“…Moreover, the D and G peaks originating from the activated carbon are evident. The I D /I G ratio [70] for the cathode is higher than the one for the anode in both cases (2.11 vs 1.68 for the supercapacitor with S1; 2.68 vs 2.21 for the supercapacitor with S5), suggesting a higher quantity of defects within the carbon atom crystals (due to R1 and R2), that is a greater presence of sp 3 hybridized carbon atoms. The full width at half maximum (FWHM) values of the cathodes are higher (i. e., the Raman peak is broader) than those of the anodes, viz., 111.1 vs 105.8 cm À 1 for S1 and 107.5 vs 100.5 cm À 1 for S5, further pointing out the greater degree of disorder and structural changes of the activated carbon, for both devices.…”

“…As a comparison, the diagram of the Mn(NO 3 ) 2 ‐ice mixture (black curve in Figure 1b) is also included. The eutectic depth ( ΔT , the ideality line connecting the melting temperatures of water and the tetrahydrate salt and the eutectic temperature) reaches 93 °C, and is greater than its counterpart Mn(NO 3 ) 2 ‐H 2 O ( ΔT =65 °C), [22] suggesting a stronger amplitude of interactions between species (anion‐H 2 O) in the eutectic mixture [28] …”

“…To this end, building on the recent breakthrough, where, for the first time, another manganese‐based salt (Mn(NO 3 ) 2 , manganese nitrate) was presented as an electrolyte in AC/Mn(NO 3 ) 2 /AC supercapacitors, [22] we present the utilization of Mn(CH 3 COO) 2 salt for a similar supercapacitor type. This salt serves a dual purpose by facilitating in‐situ MnO 2 deposition on the cathode and acting as an electrolyte for a similar‐type AC//MnO 2 supercapacitor.…”

Small Molecules, Great Powers: Chemistry of Small Organo‐Chalcogenide Molecules in Rechargeable Li‐Sulfur Batteries

“…[28] Among the chalcogenide elements, sulfur has attracted extensive attention because of its excellent theoretical capacity, but its poor electrical conductivity limits its further commercial application. [29] For selenium and tellurium elements, although the theoretical capacities are relatively low, they can effectively compensate for the poor electrical conductivity. [30][31][32] Importantly, small organo-chalcogenide molecules have the unique functional adjustability, that is, its structures can be purposefully tuned by regulating the length of sulfur chains, the type of chalcogenide elements, the length of chalcogenide chains, the structure of the carbon skeleton, and the type, number and location of the functional groups, which endow them different functionalities.…”