The solid‐state Li battery is a promising energy‐storage system that is both safe and features a high energy density. A main obstacle to its application is the poor interface contact between the solid electrodes and the ceramic electrolyte. Surface treatment methods have been proposed to improve the interface of the ceramic electrolytes, but they are generally limited to low‐capacity or short‐term cycling. Herein, an electron/ion dual‐conductive solid framework is proposed by partially dealloying the Li–Mg alloy anode on a garnet‐type solid‐state electrolyte. The Li–Mg alloy framework serves as a solid electron/ion dual‐conductive Li host during cell cycling, in which the Li metal can cycle as a Li‐rich or Li‐deficient alloy anode, free from interface deterioration or volume collapse. Thus, the capacity, current density, and cycle life of the solid Li anode are improved. The cycle capability of this solid anode is demonstrated by cycling for 500 h at 1 mA cm−2, followed by another 500 h at 2 mA cm−2 without short‐circuiting, realizing a record high cumulative capacity of 750 mA h cm−2 for garnet‐type all‐solid‐state Li batteries. This alloy framework with electron/ion dual‐conductive pathways creates the possibility to realize high‐energy solid‐state Li batteries with extended lifespans.

We have synthesized nanoporous Au with a dual microscopic length scale by exploiting the crystal structure of the alloy precursor. The synthesized mesoscopic material is characterized by stacked Au layers of submicrometer thickness. In addition, each layer displays nanoporosity through the entire bulk. It is shown that the thickness of these layers can be tailored via the grain size of the alloy precursor. The two-length-scale structure enhances the functional properties of nanoporous gold, leading to charge-induced strains of amplitude up to 6%, which are roughly 2 orders of magnitude larger than in nanoporous Au with the standard one-length-scale porous morphology. A model is presented to describe these phenomena.

High-purity Fe3S4 (greigite) microcrystals with octahedral shape were synthesized via a simple hydrothermal method using a surfactant. The as-prepared samples have the inverse spinel structure with high crystallinity. The saturation magnetization (M s) reaches 3.74 μB at 5 K and 3.51 μB at room temperature, which is larger than all reported values thus far. Electrical transport measurements show metallic behavior with a resistivity 40 times lower than in any previous report. The potential use of greigite as an anode in lithium-ion batteries was investigated by cyclic voltammery and galvanostatic discharge–charge cycling on as-prepared samples. The discharge capacity was 1161 mAh/g in the first cycle and 563 mAh/g in the 100th cycle. This excellent electrochemical performance can be attributed to the high purity, crystallinity, and favorable morphology of the products.

Secondary phases, either introduced by alloying or heat treatment, are commonly 31 present in most high-entropy alloys (HEAs). Understanding the formation of secondary 32 phases at high temperatures, and their effect on mechanical properties, is a critical issue 33 that is undertaken in the present study, using the Al x CoCrFeNi (x = 0.3, 0.5, and 0.7) as 34 a model alloy. The in-situ transmission-electron-microscopy (TEM) heating observation, 35 an atom-probe-tomography (APT) study for the reference starting materials (Al 0.3 and 36 Al 0.5 alloys), and thermodynamic calculations for all three alloys, are performed to 37 investigate (1) the aluminum effect on the secondary-phase fractions, (2) the 38 annealing-twinning formation in the face-centered-cubic (FCC) matrix, (3) the 39 strengthening effect of the secondary ordered body-centered-cubic (B2) phase, and (4) 40 the nucleation path of the secondary phase thoroughly. The present work will 41 substantially optimize the alloy design of HEAs and facilitate applications of HEAs to a 42 wide temperature range.