An automated platform that can perform standard electrochemical tests at the micro-scale will greatly facilitate the electrochemical property screening of a combinatorial materials chip. Here we report an automated test platform for high-throughput characterization of metallic materials’ local electrochemical properties. It integrates four components, including a micro-electrochemical cell, an automatic liquid refresh system, a programmed scanning automated XYZ stage, and a control system. The high-throughput test cell array is constructed using capillary and lithography techniques. The automation is achieved by a Lab View program that can control all the components. We validated the system reliability by characterizing the surface electrochemical activity of the Fe-based alloy in a Fe–Cr–Ni combinatorial materials chip. Combining electron probe micro-analysis, X-ray diffraction, and the above local electrochemical tests, the relationship between composition, crystal structure, and the electrochemical properties of the Fe-based alloy has been established and discussed. The results demonstrate that this is a highly promising technique for high-efficiency data collection for database construction and corrosion-resistant material design.

Sodium–sulfur (Na–S) batteries with durable Na‐metal stability, shuttle‐free cyclability, and long lifespan are promising to large‐scale energy storages. However, meeting these stringent requirements poses huge challenges with the existing electrolytes. Herein, a localized saturated electrolyte (LSE) is proposed with 2‐methyltetrahydrofuran (MeTHF) as an inner sheath solvent, which represents a new category of electrolyte for Na–S system. Unlike the traditional high concentration electrolytes, the LSE is realized with a low salt‐to‐solvent ratio and low diluent‐to‐solvent ratio, which pushes the limit of localized high concentration electrolyte (LHCE). The appropriate molecular structure and solvation ability of MeTHF regulate a saturated inner sheath, which features a reinforced coordination of Na+ to anions, enlarged Na+‐solvent distance, and weakened anion‐diluent interaction. Such electrolyte configuration is found to be the key to build a sustainable interphase and a quasi‐solid–solid sulfur redox process, making a dendrite‐inhibited and shuttle‐free Na–S battery possible. With this electrolyte, pouch cells with decent cycling performance under rather demanding conditions are demonstrated.

Arrhenius Crystallization of Ge2Sb2Te5 In article number 2200429, Jie Zhao, Jian Hui, Leslie H. Allen, and co‐workers investigate the crystallization of 10–40 nm thick Ge2Sb2Te5 (GST) via nanocalorimetry with a heating rate up to 1,000,000 K/s. GST shows Arrhenius kinetics and crystallization growth rate (CGV) consistent with that of actual phase‐change memory (PCM) cells. This addresses a 10‐year‐debate originated from the unexpected non‐Arrhenius kinetics uncovered by commercialized chip‐based calorimetry with CGV 103–105 higher than that of PCM devices.

Non‐volatile phase‐change memory (PCM) devices are based on phase‐change materials such as Ge2Sb2Te5 (GST). PCM requires critically high crystallization growth velocity (CGV) for nanosecond switching speeds, which makes its material‐level kinetics investigation inaccessible for most characterization methods and remains ambiguous. In this work, nanocalorimetry enters this “no‐man's land” with scanning rate up to 1 000 000 K s−1 (fastest heating rate among all reported calorimetric studies on GST) and smaller sample‐size (10–40 nm thick) typical of PCM devices. Viscosity of supercooled liquid GST (inferred from the crystallization kinetic) exhibits Arrhenius behavior up to 290 °C, indicating its low fragility nature and thus a fragile‐to‐strong crossover at ≈410 °C. Thin‐film GST crystallization is found to be a single‐step Arrhenius process dominated by growth of interfacial nuclei with activation energy of 2.36 ±  0.14 eV. Calculated CGV is consistent with that of actual PCM cells. This addresses a 10‐year‐debate originated from the unexpected non‐Arrhenius kinetics measured by commercialized chip‐based calorimetry, which reports CGV 103−105 higher than those measured using PCM cells. Negligible thermal lag (<1.5 K) and no delamination is observed in this work. Melting, solidification, and specific heat of GST are also measured and agree with conventional calorimetry of bulk samples.

High-voltage spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) is a promising nextgeneration cathode material due to its structural stability, high operation voltage, and low cost. However, the cycle life of LNMO cells is compromised by detrimental electrode−electrolyte reactions, chemical crossover, and rapid anode degradation. Here, we demonstrate that the cycling stability of LNMO can be effectively enhanced by a high-energy laser treatment. Advanced characterizations unveil that the laser treatment induces partial decomposition of the polyvinylidene fluoride binder and formation of a surface LiF phase, which mitigates electrode−electrolyte side reactions and reduces the generation of dissolved transition-metal ions and acidic crossover species. As a result, the solid electrolyte interphase of the graphite counter electrode is thin and is composed of fewer electrolyte decomposition products. This work demonstrates the potential of laser treatment in tuning the surface chemistry of cathode materials for lithium-ion batteries.