All-solid-state lithium-ion batteries have the potential to become an important class of next-generation electrochemical energy storage devices. However, for achieving competitive performance, a better understanding of the interfacial processes at the electrodes is necessary for optimized electrode compositions to be developed. In this work, the interfacial processes between the solid electrolyte (LiGePS) and the electrode materials (In/InLi and LiCoO) are monitored using impedance spectroscopy and galvanostatic cycling, showing a large resistance contribution and kinetic hindrance at the metal anode. The effect of different fractions of the solid electrolyte in the composite cathodes on the rate performance is tested. The results demonstrate the necessity of a carefully designed composite microstructure depending on the desired applications of an all-solid-state battery. While a relatively low mass fraction of solid electrolyte is sufficient for high energy density, a higher fraction of solid electrolyte is required for high power density.

Rechargeable solid-state lithium ion batteries (SSLB) require fast ion conducting solid electrolytes (SEs) to enable high charge and discharge rates. Li 7 P 3 S 11 is a particularly promising lithium solid electrolyte, exhibiting very high room temperature conductivities of up to 17 mS• cm −1 and high ductility, allowing fast ion transport through the bulk and intimate contact to high surface electrodes. Here we present a novel hot-press setup that facilitates the synthesis of solid electrolytes by combining in situ electrochemical impedance spectroscopy (EIS) with simultaneous temperature-and pressure-monitoring. While a high room temperature conductivity in the order of 10 mS•cm −1 is readily achieved for phase pure Li 7 P 3 S 11 with this design, it further enables monitoring of the different steps of crystallization from an amorphous Li 2 S−P 2 S 5 glass to triclinic Li 7 P 3 S 11 . Nucleation, crystallization andat temperatures exceeding 280 °Cdecomposition of the material are analyzed in real time, enabling process optimization. The results are supported ex situ by means of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and Raman spectroscopy. Proof-of-principle experiments show the promising cycling-and rate capability of Li 0.3 In 0.7 /Li 7 P 3 S 11 /S-composite all-solid-state batteries. It is furthermore presented that discharging below a limit of 1.2 V results in decomposition of the SE/cathode interface.

Dissolved organic matter (DOM) plays a prominent role in the transport of contaminants in porous media. As DOM has to be considered as a reactive component, flow regime and sorbent reactivity should affect overall DOM transport in an important way. We focused on DOM transport in unsaturated column experiments using quartz sand (QS) and goethite‐coated quartz sand (GS). Rate constrictions to DOM sorption were investigated by varying the volumetric flow rate, while extent and reversibility of sorption were studied in consecutive adsorption and desorption steps. In the QS, DOM retention was low and unaffected by changes in flow rate. Desorption‐step breakthrough curves (BTCs) and mass balances show full reversibility of the sorption process. However, DOM retention in GS was significant and sensitive to flow variation, indicative of nonequilibrium sorption. At lower flow rates, DOM breakthrough exhibited a change in curvature (shoulder) due to the superimposition of two BTCs representing reactive and nonreactive DOM fractions. Transport was successfully modeled assuming these two fractions governed overall DOM mobility. At higher flow rates, the BTC shoulder vanished due to reduced contact time between the DOM and the solid phase (rate‐limited sorption). Sorption of DOM on GS is accompanied by a marked rise in effluent pH, indicative of a ligand‐exchange mechanism. Recovery of DOM during desorption was incomplete due to either partially irreversible sorption or strongly rate‐limited desorption. Increased DOM mobility in the consecutive adsorption step resulted from partial blocking of sorption sites by the initial pulse of DOM.

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