Sulfur-based cathodes are promising to enable high-energy-density lithium-sulfur batteries; however, elemental sulfur as active material faces several challenges, including undesirable volume change (∼80%) when completely reduced and high dependence on liquid electrolyte wherein an electrolyte/sulfur ratio >10 μL mg is required for high material utilization. These limit the attainable energy densities of these batteries. Herein, we introduce a new class of phenyl polysulfides CHS CH (4 ≤ x ≤ 6) as liquid cathode materials synthesized in a facile and scalable route to mitigate these setbacks. These polysulfides possess sufficiently high theoretical specific capacities, specific energies, and energy densities. Spectroscopic techniques verify their chemical composition and computation shows that the volume change when reduced is about 37%. Lithium half-cell testing shows that phenyl hexasulfide (CHSCH) can provide a specific capacity of 650 mAh g and capacity retention of 80% through 500 cycles at 1 C rate along with superlative performance up to 10 C. Furthermore, 1302 Wh kg and 1720 Wh L are achievable at a low electrolyte/active material ratio, i.e., 3 μL mg. This work adds new members to the cathode family for Li-S batteries, reduces the gap between the theoretical and practical energy densities of batteries, and provides a new direction for the development of alternative high-capacity cathode materials.

Li-ion batteries have transformed personal electronics from chunky devices to lightweight, flexible, and even wearable ones. Higher capacity and energy density, along with flexibility is offered by sulfur-based cathode materials. In this work, the condensation reaction of 1,4-benzenedithiol with elemental sulfur has been utilized to synthesize polyphenylene tetrasulfide (PPTS) possessing a theoretical specific capacity of 788 mAh g −1 . This elastic material can accommodate a strain of up to 334%, while the carbon nanotube-based cathode can handle strains of 107%. This good flexibility also comes with favorable cycling performance in a lithium battery with a high capacity (633 mAh g −1 at 1 C), good rate performance, high Coulombic efficiency (∼99.4%), and a low capacity decay (under 0.07% per cycle). Therefore, PPTS and its analogues offer promising cathodes for flexible lithium batteries.

composition of the liquid-disordered phase have a diameter below optical resolution. Direct imaging of the intrinsic contact angle formed by the membrane and the two phases in budded vesicles (PRL, 103:238103, 2009) is also hindered by the poor axial resolution in confocal microscopy. Here, we use a super resolution technique, stimulated emission depletion (STED) microscopy in both 2D and 3D mode combined with microfluidics to study these remarkable membrane morphologies. We first designed a microfluidic device which can dramatically increase the trapping efficiency of giant unilamellar vesicles (GUVs) and improve the solution exchange rate. Then, with a resolution less than 35nm from STED microscopy, we visualize the membrane nanotube structures with unprecedented detail, and compare the directly measured nanotube diameters with previously reported theoretical and experimental ones. Additionally, by manipulating the height of the microfluidic channels, we pinch and orient the budded vesicles to image the intrinsic contact angle with lateral STED resolution. These highly curved membrane structures imaged with super resolution microscopy will serve to deepen and expand our understanding of biomembranes. This work is part of the MaxSynBio consortium, jointly funded by the Federal Ministry of Education and Research of Germany and the Max Planck Society.

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values of donor and acceptor probes. Since FRET depends on the distance between donors and acceptors, and this distance depends upon the domain size, this study makes possible the measurement of nanodomain size. We found domain sizes of 10.0 5 2.5 nm of radius for nanodomains in DSPC/POPC/ Chol and bSM/POPC/Chol.