Figure 7. TEM and elemental analyses of S-HMT@CNTs cathode cycled 100 times and then a-c) charged to 2.8 V and d-f) discharged to 1.9 V. g-j) SEM and EDX-elemental analyses of DF-PCW interlayer recovered from S-HMT@CNT cell cycled 100 times at 1C rate between 1.9 and 2.8 V.

A rechargeable potassium–sulfur battery based on SPAN cathode and PAA binder demonstrated high reversible capacity and excellent cycling stability.

This study summarizes nanostructured metal phosphide-based materials for battery and supercapacitor applications and the recent progress, and provides the challenges and future research trends of nanostructured metal phosphide-based materials in electrochemical energy storage applications.

Based on the reversible conversion reactions, K 2 S x (5 ≤ x ≤ 6) ⎯

Sulfurized carbonized polyacrylonitrile (S-CPAN) is a promising cathode material for Li-S batteries owing to the absence of polysulfide dissolution phenomena in the electrolyte solutions and thus the lack of a detrimental shuttle mechanism. However, challenges remain in achieving high performance at practical loading because of large volume expansion of S-CPAN electrodes and lithium anode degradation at high current densities. To mitigate this problem, we propose a novel cell design including poly(acrylic acid) (PAA) binder for improved integrity of the composite electrodes and fluoroethylene carbonate (FEC) as additive in the electrolyte solutions for stabilizing the lithium metal surface. As a result, these cells delivered high initial discharge capacity of 1500 mAh g and a superior cycling stability ∼98.5% capacity retention after 100 cycles, 0.5 C rate, and high sulfur loading of 3.0 mg cm. Scaled-up 260 mAh pouch cells are working very well, highlighting the practical importance of this work.

Designing an optimum cell configuration that can deliver high capacity, fast charge-discharge capability, and good cycle retention is imperative for developing a high-performance lithium-sulfur battery. Herein, a novel lithium-sulfur cell design is proposed, which consists of sulfur and magnesium-aluminum-layered double hydroxides (MgAl-LDH)-carbon nanotubes (CNTs) composite cathode with a modified polymer separator produced by dual side coating approaches (one side: graphene and the other side: aluminum oxides). The composite cathode functions as a combined electrocatalyst and polysulfide scavenger, greatly improving the reaction kinetics and stabilizing the Coulombic efficiency upon cycling. The modified separator enhances further Li + -ion or electron transport and prevents undesirable contact between the cathode and dendritic lithium on the anode. The proposed lithium-sulfur cell fabricated with the as-prepared composite cathode and modified separator exhibits a high initial discharge capacity of 1375 mA h g −1 at 0.1 C rate, excellent cycling stability during 200 cycles at 1 C rate, and superior rate capability up to 5 C rate, even with high sulfur loading of 4.0 mg cm −2 . In addition, the findings that found in postmortem chracterization of cathode, separator, and Li metal anode from cycled cell help in identifying the reason for its subsequent degradation upon cycling in Li-S cells.

Sulfur electrodes confined in an inert carbon matrix show practical limitations and concerns related to low cathode density. As a result, these electrodes require a large amount of electrolyte, normally three times more than the volume used in commercial Li‐ion batteries. Herein, a high‐energy and high‐performance lithium–sulfur battery concept, designed to achieve high practical capacity with minimum volume of electrolyte is proposed. It is based on deposition of polysulfide species on a self‐standing and highly conductive carbon nanofiber network, thus eliminating the need for a binder and current collector, resulting in high active material loading. The fiber network has a functionalized surface with the presence of polar oxygen groups, with the aim to prevent polysulfide migration to the lithium anode during the electrochemical process, by the formation of S–O species. Owing to the high sulfur loading (6 mg cm−2) and a reduced free volume of the sulfide/fiber electrode, the Li–S cell is designed to work with as little as 10 µL cm−2 of electrolyte. With this design the cell has a high energy density of 450 Wh kg−1, a lifetime of more than 400 cycles, and the possibility of low cost, by use of abundant and eco‐friendly materials.

Due to lithium−sulfur battery's high theoretical capacity and energy density, Li−S has been considered as a promising candidate for next-generation Li batteries. Despite this, Li−S batteries suffer from poor electrical conductivity and the shuttle effect, which result in loss of active material and active material loading limitation, thus hindering the practical application of Li−S. This Letter introduces the modified high sulfur-loading electrode (MHSE) with a loading of 10 mg cm −2 which directly addresses these two drawbacks and employs a simple production process suitable for mass production through the use of elemental sulfur. The MHSE consists of three distinct components which provide additional conductivity, mechanical support, and polysulfide adsorption ability on each level to enhance electrochemical performance. The electrode manifested an initial discharge capacity of 1332 mAh g −1 with a 91% cycle retention at the end of 50 cycles and cycled with stability from 0.1C to 2C during rate capability testing.