Developing a high-performance sulfur host is central to the commercialization and general development of lithium−sulfur batteries. Here, for the first time, we propose the concept of dynamic hosts for lithium−sulfur batteries and elucidate the mechanism through which TiS 2 acts in such a fashion, using in situ X-ray diffraction and cryogenic scanning transmission electron microscopy (cryo-STEM). A TiS 2 −S composite electrode delivered a reversible capacity of 1120 mAh g −1 at 0.3 C after 200 cycles with a capacity retention of 97.0% and capacities of 886 and 613 mAh g −1 at 1.0 C up to 200 and 1000 cycles, respectively. Our results indicate that it is Li x TiS 2 (0 < x ≤ 1), rather than TiS 2 , that effectively traps polysulfides and catalytically decomposes Li 2 S.

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Culturing cancer cells in a three-dimensional (3D) environment better recapitulates in vivo conditions by mimicking cell-to-cell interactions and mass transfer limitations of metabolites, oxygen, and drugs. Recent drug studies have suggested that a high rate of preclinical and clinical failures results from mass transfer limitations associated with drug entry into solid tumors that 2D model systems cannot predict. Droplet microfluidic devices offer a promising alternative to grow 3D spheroids from a small number of cells to reduce intratumor heterogeneity, which is lacking in other approaches. Spheroids were generated by encapsulating cells in novel thiol–acrylate (TA) hydrogel scaffold droplets followed by on-chip isolation of single droplets in a 990- or 450-member trapping array. The TA hydrogel rapidly (∼35 min) polymerized on-chip to provide an initial scaffold to support spheroid development followed by a time-dependent degradation. Two trapping arrays were fabricated with 150 or 300 μm diameter traps to investigate the effect of droplet size and cell seeding density on spheroid formation and growth. Both trapping arrays were capable of ∼99% droplet trapping efficiency with ∼90% and 55% cellular encapsulation in trapping arrays containing 300 and 150 μm traps, respectively. The oil phase was replaced with media ∼1 h after droplet trapping to initiate long-term spheroid culturing. The growth and viability of MCF-7 3D spheroids were confirmed for 7 days under continuous media flow using a customized gravity-driven system to eliminate the need for syringe pumps. It was found that a minimum of 10 or more encapsulated cells are needed to generate a growing spheroid while fewer than 10 parent cells produced stagnant 3D spheroids. As a proof of concept, a drug susceptibility study was performed treating the spheroids with fulvestrant followed by interrogating the spheroids for proliferation in the presence of estrogen. Following fulvestrant exposure, the spheroids showed significantly less proliferation in the presence of estrogen, confirming drug efficacy.

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Over the past few years, lithium sulfur (Li-S) batteries have attracted growing attention as an enabling technology because of their high energy density. The limitations to commercialize Li-S batteries originate from the intrinsic properties of sulfur: its poor electronic conductivity and the polysulfide shuttling effect. The aim of this research is to address these challenges by developing an additive for Li-S batteries. Aluminum (Al) powders prepared from soda cans were mixed with sulfur to form a composite with a sulfur mass loading up to 90 wt%. The electrochemical performance shows that the Al-S composite in Li-S cells exhibits a stable retention after 200 cycles and an ability to stabilize quickly (<10 cycles). Moreover, the rate performance of the Al-S composite is improved over conventional carbon additives. Post analysis suggests that Al-S surface interaction is a possible origin for this improvement.