Single-crystal metals have distinctive properties owing to the absence of grain boundaries and strong anisotropy. Commercial single-crystal metals are usually synthesized by bulk crystal growth or by deposition of thin films onto substrates, and they are expensive and small. We prepared extremely large single-crystal metal foils by “contact-free annealing” from commercial polycrystalline foils. The colossal grain growth (up to 32 square centimeters) is achieved by minimizing contact stresses, resulting in a preferred in-plane and out-of-plane crystal orientation, and is driven by surface energy minimization during the rotation of the crystal lattice followed by “consumption” of neighboring grains. Industrial-scale production of single-crystal metal foils is possible as a result of this discovery.

Fast charging rate and large energy storage are becoming key elements for the development of nextgeneration batteries, targeting high-performance electric vehicles. Developing electrodes with high volumetric and gravimetric capacity that could be operated at a high rate is the most challenging part of this process. Using silicon as the anode material, which exhibits the highest theoretical capacity as a lithium-ion battery anode, we report a binder-free electrode that interconnects carbon-sheathed porous silicon nanowires into a coral-like network and shows fast charging performance coupled to high energy and power densities when integrated into a full cell with a high areal capacity loading. The combination of interconnected nanowires, porous structure, and a highly conformal carbon coating in a single system strongly promotes the reaction kinetics of the electrode. This leads to fast-charging capability while maintaining the integrity of the electrode without structural collapse and, thus, stable cycling performance without using binder and conductive additives. Specifically, this anode shows high specific capacities (over 1200 mAh g −1 ) at an ultrahigh charging rate of 7 C over 500 charge−discharge cycles. When coupled with a commercial LiCoO 2 or LiFePO 4 cathode in a full cell, it delivers a volumetric energy density of 1621 Wh L −1 with a LiCoO 2 cathode and a power density of 7762 W L −1 with a LiFePO 4 cathode.

Single‐crystal electron diffraction has shown to be powerful for structure determination of nano‐ and submicron‐sized crystals that are too small to be studied by single‐crystal X‐ray diffraction. However, it has been very challenging to obtain high quality electron diffraction data from beam sensitive crystals such as metal–organic frameworks (MOFs). It is even more difficult to locate guest species in the pores of MOF crystals. Here, we present synthesis of a novel porous cobalt MOF with 1D channels, [Co2(Ni‐H4TPPP)]⋅2 DABCO⋅6 H2O, (denoted Co‐CAU‐36; DABCO=1,4‐diazabicyclo[2.2.2]octane), and its structure determination using continuous rotation electron diffraction (cRED) data. By combining a fast hybrid electron detector with low sample temperature (96 K), high resolution (0.83–1.00 Å) cRED data could be obtained from eight Co‐CAU‐36 crystals. Independent structure determinations were conducted using each of the eight cRED datasets. We show that all atoms in the MOF framework could be located. More importantly, we demonstrate for the first time that organic molecules in the pores, which were previously difficult to find, could be located using the cRED data. A comparison of eight independent structure determinations using different datasets shows that structural models differ only on average by 0.03(2) Å for the framework atoms and 0.10(6) and 0.16(12) Å for DABCO and water molecules, respectively.

The phase transition from the kinetically favored tetragonal form II into the thermodynamically stable hexagonal form I is the general phenomenon and core issue in application of polybutene-1-based materials. It is known that the variation of molecular structure by copolymerizing counits and the imposition of external stretching both greatly affect the phase transition. In this work, a series of butene-1/4-methyl-1-pentene (4M1P) random copolymers were synthesized with the dimethylpyridyl­amidohafnium/organoboron catalyst, where the 4M1P incorporated is the counit type of depressing II–I phase transition. Mechanical tests were combined with the in-situ wide-angle X-ray diffraction (WAXD) method to study the competing effects of the presence of 4M1P counits and stretching on the II–I phase transition. First of all, the quiescent experiments reveal that addition of 4M1P counits not only slows down transition kinetics but also decreases the ultimate form I fraction in the transition plateau. The 4M1P concentration ≥3.40 mol % is high enough to completely impede the II–I phase transition even when the aging time is as long as 4 months. Second, the stretching-induced phase transition was explored with the combined structural and mechanical information from WAXD and mechanical characterizations, respectively. The influence of stretching stimuli in the phase transition varies with 4M1P concentration. For low 4M1P concentration ≤1.00 mol %, stretching significantly accelerates the transition kinetics and induces the complete transition of form II. For intermediate 4M1P concentration 3.40 mol %, stretching effectively triggers the occurrence of the II–I phase transition, which does not start under quiescent conditions but only induces partial transition until fracture. For high 4M1P concentration ranging from 7.80 to 30.1 mol %, stretching just orientates the form II crystallites without starting any phase transition to form I. Third, as the concentration of 4M1P counits is increased, the phase transition is accomplished with different orientations, which determines the microscopic stress applied to lamellae. Then, detailed kinetics of the II–I phase transition was correlated to the stretching stimuli of the total true stress, component stresses parallel and perpendicular to the c-axis in the crystal lattice. It was interesting to find that transition kinetics is dominated by the component stress perpendicular to the c-axis for the off-axis orientation pathway. For the molecular mechanism of the phase transition, this indicates that the activated chain lateral slip is the dominant process for nucleation of form I within original form II.