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Lithium sulfide (Li2S) is a promising alternative cathodic material for lithium–sulfur batteries, which can alleviate the volume expansion of sulfur‑based cathodes. As a fully lithiated cathode, Li2S can be paired with Li-free anodes, thereby increasing the selectivity of anodic materials. Nevertheless, Li2S cathode is hindered by its high cost, harsh preparation conditions, and inadequate conductivity, which impose limitations on its practical application. Hence, the crucial factor in enabling the practicality of Li2S cathode is the development of low-cost and facile synthetic methods to produce highly conductive Li2S material. Herein, a high‑conductivity Li2S@C/CNT composite cathode is prepared using low-cost Li2SO4 as a lithium source through a facile spray drying technique combined with carbothermal reduction method. Benefiting from the high-speed three-dimensional pathway for electron transport provided by the in-situ formed botryoidal highly conductive network, the Li2S@C/CNT cathode exhibits ultrahigh initial discharge capacity (1028.5 mA h g− 1@1 C), superior cycle stability (520.6 mA h g− 1 after 200 cycles), and remarkable rate capability (301.8 mA h g− 1@5 C). This work not only presents a simple and feasible approach for the low-cost preparation of high‑performance Li2S cathode, but also proposes an innovative idea for advancing the development of high energy density lithium–sulfur batteries. [ABSTRACT FROM AUTHOR]

All-solid-state lithium–sulfur batteries are considered one of the most promising candidates for energy storage devices due to their high energy density and safety. However, the poor electron transport of sulfur-based cathodes significantly reduces their reaction kinetics, resulting in low utilization efficiency and subpar rate performance. Herein, leveraging the similar chemical properties of sulfur and selenium, we uniformly deposit SexS1−x (x = 0–0.3) solid solutions with different selenium content on the surface of active carbon via a facile melt-diffusion method to achieve SexS1−x@AC (x = 0–0.3) composite materials. The introduction of selenium effectively enhances the lithium-ion diffusion coefficient of the SexS1−x@AC (x = 0–0.3) cathodes, and improves the stability of the cathode/solid electrolyte interface. With the increase in selenium content, the reaction kinetics of the SexS1−x@AC (x = 0–0.3) cathodes are altered. Specifically, the average lithium-ion diffusion coefficients for the S@AC and Se0.2S0.8@AC cathodes are 6.11 × 10−14 and 1.65 × 10−13 cm2 s−1, respectively, showing a twofold increase. Concurrently, the Se0.2S0.8@AC cathode exhibits higher discharge capacity (698.8 mA h g−1) than that of the S@AC cathode (501.3 mA h g−1) at 1 A g−1. Surprisingly, even when the mass loading increases to 8.85 mg cm−2, the Se0.2S0.8@AC cathode still shows superior cycling stability, which is attributed to the fast ionic/electronic transport pathways within the cathode. Moreover, the Se0.2S0.8@AC cathode maintains good physical contact at the cathode/SE interface after cycling. In all-solid-state lithium–sulfur batteries, the introduction of selenium in the sulfur cathode enhances reaction kinetics (1.65 × 10−13 cm2 s−1), provides additional reactive sites, and significantly improves the electrochemical performance of Se0.2S0.8@AC even with high mass loading (8.85 mg cm−2). [ABSTRACT FROM AUTHOR]

Pursuit of advanced batteries with high‐energy density is one of the eternal goals for electrochemists. Over the past decades, lithium–sulfur batteries (LSBs) have gained world‐wide popularity due to their high theoretical energy density and cost effectiveness. However, their road to the market is still full of thorns. Apart from the poor electronic conductivity of sulfur‐based cathodes, LSBs involve special multielectron reaction mechanisms associated with active soluble lithium polysulfides intermediates. Accordingly, the electrode design and fabrication protocols of LSBs are different from those of traditional lithium ion batteries. This review is aimed at discussing the electrode design/fabrication protocols of LSBs, especially the current problems on various sulfur‐based cathodes (such as S, Li2S, Li2Sx catholyte, organopolysulfides) and corresponding solutions. Different fabrication methods of sulfur‐based cathodes are introduced and their corresponding bullet points to achieve high‐quality cathodes are highlighted. In addition, the challenges and solutions of sulfur‐based cathodes including active material content, mass loading, conductive agent/binder, compaction density, electrolyte/sulfur ratio, and current collector are summarized and rational strategies are refined to address these issues. Finally, the future prospects on sulfur‐based cathodes and LSBs are proposed. [ABSTRACT FROM AUTHOR]

A three-dimensional laminated carbon–sulfur composite cathode (rGO-TC/S) is prepared by embedding sulfur in Trichoderma derived carbon hosts with the assistance of supercritical CO 2 fluid and flanking it with rGO supporting layers via vacuum filtration. Li-S batteries with laminated rGO-TC/S cathode exhibit superior electrochemical performance at 0.1 A g−1. [Display omitted] • Trichoderma spores derived biomass carbon has superior polysulfide adsorbability. • Supercritical CO 2 treatment makes S evenly distribute into carbon hosts. • Laminated S cathode shows enhanced electrochemical performance with high S loading. • RGO barrier layers contribute to improving conductivity and confining polysulfide. The commercialization of lithium-sulfur (Li-S) batteries is limited by the poor electrochemical properties under actual working conditions, which is mainly due to the slow cathodic redox kinetics and serious polysulfides shuttling. In this work, we report a novel free-standing sulfur cathode to address aforementioned issues, in which sulfur is encapsulated in Trichoderma spores derived carbon hosts (TC) with the assistance of supercritical CO 2 (SC-CO 2) fluid technology. This free-standing sulfur cathode has a "sandwich" structure with three-dimensional (3D) highly conductive network constructed by reduced graphene oxide (rGO). SC-CO 2 fluid with superior solubility, high permeability and rapid diffusion can achieve the uniform distribution of sulfur and high sulfur loading in TC/S composites. Meanwhile, the novel "sandwich" structure not only provides high mechanical strength, but also inhibits soluble polysulfide shuttling, as well as improves redox kinetics of sulfur. As a result, a reversible discharge capacity of > 755 mA h g−1 after 100 cycles at 0.1 A g−1, and a high Coulombic efficiency of 97.9% can be achieved at high areal S loading (3 mg cm−2). This work offers a new perspective on the electrode structure design of high loading sulfur cathode for high energy density Li-S batteries. [ABSTRACT FROM AUTHOR]

• G/T-NF@CNT foam skeleton acts as current collector to thick sulfur cathode. • NF@CNT conductive framework guarantees excellent electrical contact to sulfur. • N-doping carbon skeleton and G/T modified layer effectively anchor polysulfides. • G/T-NF@CNT/S cathode has high areal capacity and superior cycling stability. The intrinsic contradiction between high loading and high capacity in sulfur cathode severely limits the commercial viability of Li-S batteries. Herein, Graphene/TiO 2 decorated N-doped carbon foam (G/T-NF@CNT) is proposed as three-dimensional (3D) current collector for high loading sulfur cathode. This rationally designed current collector can not only provide enough space to accommodate active sulfur, but also endow sulfur cathode with strong polysulfide confining ability. More interestingly, 3D porous conductive structure has sufficient channels to realize rapid mass mobilization; meanwhile the high conductivity networks boost transfer kinetics of electrons. The electrochemical measurements demonstrate that G/T-NF@CNT/S cathode has a remarkable capacity of 788 mA h g−1 (5.83 mA h cm-2) at 0.1 A g−1 after 100 cycles with a high sulfur loading of 7.4 mg cm-2. This work provides new insights on multifunctional current collectors for thick sulfur cathodes in Li-S batteries. [ABSTRACT FROM AUTHOR]