Printed secondary batteries have market potential in two main fields -highly customized personal electronic devices, and smallscale battery production. While many different technologies may be utilized to produce a printed battery, drop-on-demand (DoD) dispensing has the advantage of being highly tailor-made, notably with the ability to produce both very thin and thick batteries. We report the cathode printing protocols, morphology and electrochemical properties of patterned electrodes. Our electrode inks are aqueous, with obvious environmental and processing benefits. We chose to study the lithium iron phosphate (LFP) cathode because of its excellent electrochemical performance. DoD-printed LFP cathodes exhibit close to theoretical capacity value, highrate capability and close to 100% coulombic efficiency. The similarity of the voltage profiles, electrochemical performance and impedance components of the AC spectra of lithium cells with printed LFP cathodes to those of commercial electrodes, indicates that printing does not alter the charge/discharge mechanism of active electrode material.

The chemical compatibility of the various compounds and elements used in lithium‐based batteries dictates their safe operation parameters and performance. The lithium salt Li‐bis(trifluoromethanesulfonyl)imide (LiTFSI) has many advantages over the common LiPF6 salt as it does not react with water impurities to form, for example, hydrofluoric acid. To further accommodate safe‐operation chemistry, we use a non‐volatile disiloxane‐based solvent 1,3‐bis(cyanopropyl)tetramethyldisiloxane (TmdSx‐CN). This is a liquid disiloxane functionalized with terminal nitrile groups. In this paper, we report on the electrochemical characterization and the composition of the solid electrolyte interphase (SEI) of 1 mol kg−1 LiTFSI dissolved in TmdSx‐CN in silicon‐lithium batteries. Specifically, we study the SEI formation on silicon nanowire anodes and its composition by several ex‐situ surface techniques (XPS, SEM), and in‐situ via polarization modulation infrared reflectance absorption spectroscopy (PM‐IRRAS). We evaluate the potential application of TmdSx‐CN to silicon‐lithium batteries and conclude that the addition of fluoroethylene carbonate (FEC) at low concentrations (10 wt %) is essential to the formation of an effective SEI. We anticipate that our study will encourage the investigation, design and use of siloxane‐based solvents as safer alternatives to common solvents used in Li‐ion batteries, and specifically as candidate solvents in Li‐metal and silicon‐anode based batteries.

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Nanostructure / Microemulsions / DDAB / Cryo-SEMWe applied cryogenic-temperature scanning electron microscopy (cryo-SEM) to perform a first direct-imaging study of single-phase microemulsions of didodecyldimethylammonium bromide (DDAB), isooctane, and water. The structural changes from a bicontinuous network to an oilcontinuous structure, observed upon the addition of water to the system, are consistent with previous indirect investigations, thus validating the model of Ninham, Evans, and coworkers, published in 1984, and demonstrating the power of this novel methodology.