Antibiotics are typically more effective against replicating rather than nonreplicating bacteria. However, a major need in global health is to eradicate persistent or nonreplicating subpopulations of bacteria such as Mycobacterium tuberculosis (Mtb). Hence, identifying chemical inhibitors that selectively kill bacteria that are not replicating is of practical importance. To address this, we screened for inhibitors of dihydrolipoamide acyltransferase (DlaT), an enzyme required by Mtb to cause tuberculosis in guinea pigs and used by the bacterium to resist nitric oxide-derived reactive nitrogen intermediates, a stress encountered in the host. Chemical screening for inhibitors of Mtb DlaT identified select rhodanines as compounds that almost exclusively kill nonreplicating mycobacteria in synergy with products of host immunity, such as nitric oxide and hypoxia, and are effective on bacteria within macrophages, a cellular reservoir for latent Mtb. Compounds that kill nonreplicating pathogens in cooperation with host immunity could complement the conventional chemotherapy of infectious disease.

The electrochemical performance of cells with a Li 1.03 (Ni 0.5 Co 0.2 Mn 0.3 ) 0.97 O 2 (NCM523) positive electrode and a blended silicongraphite (Si-Gr) negative electrode are investigated using various electrolyte compositions and voltage cycling windows. Voltage profiles of the blended Si-Gr electrode show a superposition of graphite potential plateaus on a sloped Si profile with a large potential hysteresis. The effect of this hysteresis is seen in the cell impedance versus voltage data, which are distinctly different for the charge and discharge cycles. We confirm that the addition of compounds, such as vinylene carbonate (VC) and fluoroethylene carbonate (FEC) to the baseline 1.2 M LiPF 6 in ethylene carbonate (EC): ethyl methyl carbonate (EMC) (3:7 w/w) electrolyte, improves cell capacity retention with higher retention seen at higher additive contents. We show that reducing the lower cutoff voltage (LCV) of full cells to 2.5 V increases the Si-Gr electrode potential to 1.12 V vs. Li/Li + ; this relatively-high delithiation potential correlates with the lower capacity retention displayed by the cell. Furthermore, we show that raising the upper cutoff voltage (UCV) can increase cell energy density without significantly altering capacity retention over 100 charge-discharge cycles. The development of new high-energy electrochemical couples is important to reducing the overall cost and weight per kWh of Li-ion batteries. Silicon and silicon-containing blended electrodes have been a focus of much recent research as an alternative to the commercial graphite-based negative electrode because of the substantially higher theoretical capacity of silicon (3579 mAh g −1 , Li 15 Si 4 ) compared to that of graphite (372 mAh g −1 , LiC 6 ); the higher capacity enables reduction of the negative electrode weight thereby increasing energy density of the cell. However, concerns including electrode integrity and durability related to the substantial volume expansion/contraction (∼300%) of silicon during lithiation/delithiation reactions have hampered the use of silicon as a direct substitute for graphite.Several strategies to overcome the durability problems target design of the composite electrode and its components. For example, purposely-designed silicon particle morphologies 1-3 and the use of graphene 4,5 are reported to improve the cycle life of electrodes in cells with a Li-metal counter electrode (half-cells). The choice of binders also greatly influences electrode coherence; 6-10 for example lithiated polyacrylic acid (LiPAA) has been shown to increase cycle life compared to e.g. polyvinylidene fluoride (PVDF). 6,8,10 Direct incorporation and mixing of silicon particles into standard graphite slurries also provides a means of incrementally improving electrode capacity, while retaining the higher durability of graphite electrodes. 11-13In addition to variations in the electrode constitution, alternative electrolytes are being studied to improve cell cycling stability by tuning the electrochemical interfaces. The use ...

Direct regeneration of spent Li-ion batteries based on the hydrothermal relithiation of cathode materials is a promising next-generation recycling technology. In order to demonstrate the feasibility of this approach at a large scale, we systematically design and optimize the process parameters to minimize both energy and raw material costs. Specifically, the effects of regenerative processing parameters on the composition, structure, and electrochemical performance of the regenerated cathode materials are investigated via systematic characterization and testing. From this analysis, it was found that the raw material costs can be substantially reduced by either replacing the typically employed 4 M LiOH solution by a cost-effective mixture of 0.1 M LiOH and 3.9 M KOH or recycling of the concentrated 4 M LiOH for continuous relithiation processes. Life cycle analysis suggests that this strategy results in reduced energy consumption and greenhouse gas emissions, leading to an increased potential revenue, particularly when compared with hydro-and pyrometallurgical recycling methods.

The energy density of lithium-ion cells can be significantly increased by the use of silicon-containing negative electrodes. However, the long-term performance of these cells is limited by the stability of the silicon electrode-electrolyte interface, which is continually disrupted during electrochemical cycling. Therefore, the development of electrolyte systems that enhance the stability of this interface is a critical need. In this article, we examine the cycling of ∼20 mAh pouch cells with lithium bis(fluorosulfonyl)imide (LiFSI)-containing carbonate-based electrolytes, silicon-graphite negative electrodes, and Li 1.03 (Ni 0.5 Co 0.2 Mn 0.3 ) 0.97 O 2 based positive electrodes. The effect of fluoroethylene carbonate (FEC) and vinylene carbonate (VC) addition on cell performance is also examined and compared to the performance of our baseline LiPF 6 -containing cells. Our data show that cells containing only LiFSI show rapid loss of capacity, whereas additions of FEC and VC significantly improve cell capacity retention. Furthermore, the performance of LiFSI-FEC and LiPF 6 -FEC cells are very similar indicating that the electrolyte salts play a much smaller role in performance degradation than the electrolyte solvent. Future efforts to enhance longevity of cells with silicon-graphite negative electrodes will thereby focus on developing alternative solvent systems. The ever-increasing demand for high energy density lithium-ion cells has led to a resurgence of interest in silicon-based negative electrodes.1-4 Unlike conventional graphite-based negative electrodes which have a theoretical capacity of 372 mAh/g-graphite, siliconbased negative electrodes can deliver capacities up to 3579 mAh/gsilicon, thus making possible the development of thinner, highercapacity electrodes. However, the commercialization of silicon anodes has been limited by factors that include the following: (a) the relatively large amounts of conduction additives required to ensure good interparticle electric conductivity because of silicon's semi-conducting nature; (b) the large volume expansion/contraction resulting from silicon lithiation/delithiation processes leading to excessive cracking and delamination from the current collector; (c) the development of binder-systems that can maintain cohesion between the coating components and adhesion to the current collector during electrochemical cycling; (d) the excessive solid electrolyte interphase (SEI) formation on the electrodes that irreversibly trap lithium leading to rapid capacity fade. 1In order to improve the performance of silicon-based negative electrodes, researchers have developed various strategies that include the following: (a) nanosizing the silicon particles, whereby the spaces between the particles can accommodate the volume expansion of individual particles; the use of nanoparticles, nanowires, and nanotubes have been shown to significantly improve cyclability; 5-7 (b) using non-traditional binders including water soluble polymers, such as polyacrylic acid (PAA), carboxymethyl ...