Whereas standard transmission electron microscopy studies are unable to preserve the native state of chemically reactive and beam-sensitive battery materials after operation, such materials remain pristine at cryogenic conditions. It is then possible to atomically resolve individual lithium metal atoms and their interface with the solid electrolyte interphase (SEI). We observe that dendrites in carbonate-based electrolytes grow along the <111> (preferred), <110>, or <211> directions as faceted, single-crystalline nanowires. These growth directions can change at kinks with no observable crystallographic defect. Furthermore, we reveal distinct SEI nanostructures formed in different electrolytes.

The physiochemical properties of the solid-electrolyte interphase, primarily governed by electrolyte composition, have a profound impact on the electrochemical cycling of metallic lithium. Herein, we discover that the effect of nitrate anions on regulating lithium deposition previously known in ether-based electrolytes can be extended to carbonate-based systems, which dramatically alters the nuclei from dendritic to spherical, albeit extremely limited solubility. This is attributed to the preferential reduction of nitrate during solid-electrolyte interphase formation, and the mechanisms behind which are investigated based on the structure, ion-transport properties, and charge transfer kinetics of the modified interfacial environment. To overcome the solubility barrier, a solubility-mediated sustained-release methodology is introduced, in which nitrate nanoparticles are encapsulated in porous polymer gel and can be steadily dissolved during battery operation to maintain a high concentration at the electroplating front. As such, effective dendrite suppression and remarkably enhanced cycling stability are achieved in corrosive carbonate electrolytes.

The solid electrolyte interphase (SEI) forms on all lithium battery anodes during operation and dictates their performance. Using cryoelectron microscopy, we stabilize these reactive materials for atomic-scale observation and correlate their nanostructure with battery performance. By imaging at various stages of battery operation, we reveal that the distribution of crystalline domains within the SEI is critical for the uniform transport of lithium ions. This establishes the important role that the SEI nanostructure plays in determining the performance of a battery.

A label-free electrochemical impedance immunosensor for rapid detection of Escherichia coli O157:H7 was developed by immobilizing anti-E. coli antibodies onto an indium-tin oxide interdigitated array (IDA) microelectrode. Based on the general electronic equivalent model of an electrochemical cell and the behavior of the IDA microelectrode, an equivalent circuit, consisting of an ohmic resistor of the electrolyte between two electrodes and a double layer capacitor, an electron-transfer resistor, and a Warburg impedance around each electrode, was introduced for interpretation of the impedance components of the IDA microelectrode system. The results showed that the immobilization of antibodies and the binding of E. coli cells to the IDA microelectrode surface increased the electron-transfer resistance, which was directly measured with electrochemical impedance spectroscopy in the presence of [Fe(CN)(6)](3-/4-) as a redox probe. The electron-transfer resistance was correlated with the concentration of E. coli cells in a range from 4.36 x 10(5) to 4.36 x 10(8) cfu/mL with the detection limit of 10(6) cfu/mL.

Impedance biosensor chips were developed for detection of Escherichia coli O157:H7 based on the surface immobilization of affinity-purified antibodies onto indium tin oxide (ITO) electrode chips. The immobilization of antibodies onto ITO chips was carried out using an epoxysilane monolayer to serve as a template for chemical anchoring of antibodies. The surface characteristics of chips before and after the binding reaction between the antibodies and antigens were characterized by atomic force microscopy (AFM). The patterns of the epoxysilanes monolayer, antibodies, and E. coli cells were clearly observed from the AFM images. Alkaline phosphatase as the labeled enzyme to anti-E. coli O157:H7 antibody was used to amplify the binding reaction of antibody-antigen on the chips. The biocatalyzed precipitation of 5-bromo-4-chloro-3-indolyl phosphate by alkaline phosphatase on the chips in pH 10 PBS buffer containing 0.1 M MgCl2 increased the electron-transfer resistance for a redox probe of Fe(CN)6(3-/4-) at the electrode-solution interface or the electrode resistance itself. Electrochemical impedance spectroscopy and cyclic voltammetric method were employed to follow the stepwise assembly of the systems and the electronic transduction for the detection of E. coli. The biosensor could detect the target bacteria with a detection limit of 6 x 10(3) cells/mL. A linear response in the electron-transfer resistance for the concentration of E. coli cells was found between 6 x 10(4) and 6 x 10(7) cells/mL.

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Selective atomic layer deposition of LiF on h-BN as an interfacial layer enables stable cycling of Li metal anodes.