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A “support reduction strategy” is reported to construct spatially adjacent, highly dispersed Pt and CeO2 sites in the (Pt/4nmCeO2)/SiO2 pyramid-type catalyst. Pt species are selectively trapped in the surface reductive sites on 4 nm CeO2 nano-islands.

The creation of a high-pressure rhombohedral phase leads to a colossal barocaloric effect in KPF6.

The novel 12-layered hexagonal perovskite Ba4SbMn3O12 displays Sb/Mn cationic order and a ferromagnetic spin glass transition at Tg = ∼11.5 K from a high temperature paramagnetic state of the Mn3 magnetic cluster.

The subtle difference in the cationic size and covalent bonding between Ga and Ge enables B-site mixed Ga/Ge tetrahedral centers to confine the concentration and mobility of interstitial oxygen in mellite family.

The evolution of anionic nanoclusters at the electrode interface due to cation–π interactions.

The mechanical properties of metallic materials often significantly deteriorate when used under harsh conditions, particularly at cryogenic temperatures. Yet, safe and lasting low-temperature infrastructures are needed to realize the growing global demand for liquid energy carriers such as hydrogen[1]. Traditional microstructure strategies designed for high strength and ductility at room temperature often fail when exposed to such low temperatures due to the unresolved conflict between strength and damage tolerance under such conditions[2, 3]. Here we introduce a new type of dual-scale atomic ordering nanostructure embedded in a massive metallic solid solution matrix to overcome this challenge. This reconciles advantages of two antagonistic mechanisms in one material concept, namely, a well-balanced enthalpy-driven ordering on the one hand and entropy-driven solid solution on the other. We realize the approach in form of an exceptionally high number density of coexisting sub-nanoscale chemical short-range ordered (SRO, ~2.4×10^26 m-3) and nanoscale long-range ordered (NLRO, ~4.5×10^25 m-3) zones in a CoNiV-based compositionally complex alloy. We observe several types of interactions between the chemical ordering and the dislocations, i.e., the defects that carry both, the material’s inelastic deformation and potentially also its damage initiation. We observe an ordering-induced increase in dislocation shear stress (providing strength) as well as a more rapid dislocation multiplication due to the frequent blocking of the planar dislocation flux by NLRO and the associated generation of new dislocations (providing ductility). The latter effect also releases stress concentrations at NLRO obstacles that otherwise would promote damage initiation and failure (a phenomenon observed in materials with larger ordered zones and precipitates). Consequently, a higher strength-ductility combination (strength-elongation product 76.5 GPa% with 1172 MPa yield strength at 87 K) is achieved in comparison to reference materials devoid of such ordering hierarchy (yield strength 794 MPa), containing only SRO (yield strength 931 MPa) or coherent precipitates of a few tens of nanometers (strength-elongation product 38.8 GPa%). Our results thus reveal the effects of different types (and scales) of coexisting chemical ordering on mechanical properties of complex alloys and provide guidelines to control them, which serves as a new design approach for strong and tough materials particularly for cryogenic applications.

To harvest and reuse low-temperature waste heat, we propose and realize an emergent concept—barocaloric thermal batteries based on the large inverse barocaloric effect of ammonium thiocyanate (NH 4 SCN). Thermal charging is initialized upon pressurization through an order-to-disorder phase transition, and the discharging of 43 J g −1 takes place at depressurization, which is 11 times more than the input mechanical energy. The thermodynamic equilibrium nature of the pressure-restrained heat-carrying phase guarantees stable long-duration storage. The barocaloric thermal batteries reinforced by their solid microscopic mechanism are expected to substantially advance the ability to take advantage of waste heat.

The improvement of electrochemical performance of lithium-ion (Li-ion) batteries requires in-depth understanding on the structural evolution of electrodes during electrochemical cycling. By taking advantages of sensitive, penetrative and nondestructive properties of neutrons, we adopted in operando neutron diffraction technique to explore structural characteristics of electrodes in LiNi0.5Co0.2Mn0.3O2/Graphite full cell during cycling in real time. It is revealed that the concentration of Li/Ni antisite defects varies and presents regular volcano shape in layered cathode during cycling due to the competition effect between delithiation and magnetic frustration. Moreover, visualization of the Li-ion migration pathway in cathode by maximum entropy method indicates that lithium ions diffuse via tetrahedral site hopping path at the initial state of charge, but a newly-discovered indirect zigzag hopping path dominates afterwards. As for graphite anode counterpart, the intercalation of lithium ions into anode undergoes few distinct stages, including the formation of an intermediate phase with lithium gradient. All these observations concerning the simultaneous structural variation of both cathode and anode unveil the underlying migration behavior of lithium ions in NCM/Graphite full cell and enlighten us to devise an optimized pathway for Li-ion migration toward achieving high-performance Li-ion batteries.

The continuous breaking and reforming of VO4 tetrahedra in scheelite BiVO4 is mainly affected by the acceptor dopant size.

A new germanate mixed electronic and oxide ionic conductor In1.8Zn0.2Ge2O6.9 was developed, which exhibits two-dimensional anisotropic transport nature by oxygen exchange between adjacent Ge2O7 units, with a conductivity of 1.62 × 10–2 S cm−1 at 1000 °C.

The Li-rich layered oxide is considered as one of the most promising cathode materials for high energy density batteries, due to its ultrahigh capacity derived from oxygen redox. Although incorporating over-stoichiometric Li into layered structure can generate Li2MnO3-like domain and enhance the oxygen redox activity thermodynamically, the fast and complete activation of the Li2MnO3-like domain remains challenging. Herein, we performed a systematic study on structural characteristics of Li-rich cathode materials to decipher the factors accounting for activation of oxygen redox. We reveal that the activation of Li-rich cathode materials is susceptible to local Co coordination environments. The Co ions can intrude into Li2MnO3-like domain and modulate the electronic structure, thereby facilitating the activation of Li-rich layered cathode materials upon first charging, leading to higher reversible capacity. In contrast, Li2MnO3-like domain hardly contains any Ni ions which contribute little to the activation process. The optimum composition design of this class of materials is discussed and we demonstrate a small amount of Co/Mn exchange in Li2MnO3-like domain can significantly promote the oxygen redox activation. Our findings highlight the vital role of Co ions in the activation of oxygen redox Li-rich layered cathode materials and provide new insights into the pathway toward achieving high-capacity Li-rich layered cathode materials.

Mixed electronic and oxide ion conduction was enabled in digermanate La2−xCaxGe2O7−x/2. Oxygen vacancy was stabilized and transported by sharing oxygen and oxygen exchange between Ge3O10 and GeO4 units, showing three-dimensional oxide ion transport.

Direct conversion of methane (CH4 ) to fuels and other high value-added chemicals is an attractive technology in the chemical industry; however, practical challenges to sustainable processes remain. Herein, we report the preparation of a heterostructured Co-doped MgO-based catalyst through topological transformation of a MgCo-layered double hydroxide (LDH) calcination from 200 to 1100 °C. Remarkably, the catalyst can activate CH4 coupling to produce C2 H6 with a selectivity of 41.60 % within 3 h under full-spectrum irradiation through calcination of LDH at 800 °C. Characterization studies and catalytic results suggest that the highly dispersed active sites and large interfaces amongst the Co-doped MgO-based catalysts enable surface activation of CH4 to methyl (CH3 *), in turn promoting coupling of CH3 * to C2 H6 . This study introduces a promising pathway for photodriven CH4 coupling to give high value-added chemicals by using layered double hydroxides as a precursor.

Li-ion-conducting chloride solid electrolytes receive considerable attention due to their physicochemical characteristics such as high ionic conductivity, deformability and oxidative stability. However, the raw materials are expensive, and large-scale use of this class of inorganic superionic conductors seems unlikely. Here, a cost-effective chloride solid electrolyte, Li2ZrCl6, is reported. Its raw materials are several orders of magnitude cheaper than those for the state-of-the-art chloride solid electrolytes, but high ionic conductivity (0.81 mS cm–1 at room temperature), deformability, and compatibility with 4V-class cathodes are still simultaneously achieved in Li2ZrCl6. Moreover, Li2ZrCl6 demonstrates a humidity tolerance with no sign of moisture uptake or conductivity degradation after exposure to an atmosphere with 5% relative humidity. By combining Li2ZrCl6 with the Li-In anode and the single-crystal LiNi0.8Mn0.1Co0.1O2 cathode, we report a room-temperature all-solid-state cell with a stable specific capacity of about 150 mAh g–1 for 200 cycles at 200 mA g–1., Stable inorganic solid electrolytes are instrumental in developing high-voltage Li metal batteries. Here, the authors present the synthesis and electrochemical energy storage properties of a cost-effective and humidity-tolerant chloride solid electrolyte.

Nonlinear optical (NLO) switchable materials have attracted intense attention because of their promising applications in optoelectronic devices. However, previous studies are mainly limited to mole...

The discovery of the (Li1-xFexOH)FeSe superconductor has aroused significant interest in metal hydroxide-intercalated iron chalcogenides. However, all efforts made to intercalate NaOH between FeSe and FeS layers have failed so far. Here we report two NaOH-intercalated iron chalcogenides (Na1-xOH)Fe1-yX (X = Se, S) that were synthesized by a low-temperature hydrothermal ion-exchange method. Their crystal structures were solved through single-crystal X-ray diffraction and refined against powder X-ray and neutron diffraction data. Different from the (Li1-xFexOH)FeX superconductors that crystallize in a tetragonal space group P4/nmm with Z = 2, (Na1-xOH)Fe1-yX belong to an orthorhombic space group Cmma with Z = 4. The structural solution also reveals that there are vacancies in both Na and Fe sites and there are not iron ions in the (Na1-xOH) layer. This is probably why both Fe(II) and Fe(III) species exist in the title compounds, as detected by X-ray photoelectron spectroscopy. Based on magnetization and electrical resistivity measurements, the two compounds were found to be paramagnetic semiconductors. The absence of superconductivity should be closely related to the iron vacancies in the Fe1-yX layer. Theoretical calculations suggest that inducing superconductivity in (Na1-xOH)Fe1-ySe is promising due to the similarity of the electronic structures between stoichiometric (NaOH)FeSe and the (Li1-xFexOH)FeSe superconductor.

Discovery of new high-conductivity solid-state ionic conductors has been a long-lasting interest in the field of solid-state ionics for their important applications in solid-state electrochemical devices. Here, we report the mixed oxide-ion and Li-ion conductions, together with their conducting mechanisms in the Li2W2O7 material with triclinic symmetry. The process for the ionic identity is supported by several electrochemical measurements including electrochemical impedance spectroscopy, DC polarization, oxygen concentration cell, and theoretical analysis of neutron diffraction data and bond-valence-based energy landscape calculations. We show from electrochemical measurements strong evidences of the predominating oxide-ion conducting and minor Li-ion chemistry in Li2W2O7 at high temperatures, while the bond-valence-based energy landscape analysis reveals possible multidimensional ionic migration pathways for both oxide-ions and Li-ions. Thus, the presented results provide fundamental insights into new mixed ionic conduction mechanisms in low-symmetry materials and have implications for discoveries of new ionic conductors in years to come.

Oxygen release and irreversible cation migration are the main causes of voltage fade in Li-rich transition metal oxide cathode. But their correlation is not very clear and voltage decay is still a bottleneck. Herein, we modulate the oxygen anionic redox chemistry by constructing Li2ZrO3 slabs into Li2MnO3 domain in Li1.21Ni0.28Mn0.51O2, which induces the lattice strain, tunes the chemical environment for redox-active oxygen and enlarges the gap between metallic and anionic bands. This modulation expands the region in which lattice oxygen contributes capacity by oxidation to oxygen holes and relieves the charge transfer from anionic band to antibonding metal–oxygen band under a deep delithiation. This restrains cation reduction, metal–oxygen bond fracture, and the formation of localized O2 molecule, which fundamentally inhibits lattice oxygen escape and cation migration. The modulated cathode demonstrates a low voltage decay rate (0.45 millivolt per cycle) and a long cyclic stability., Voltage fade is a critical issue for Li-rich transition metal oxide cathode. Here, the authors modulate the oxygen anionic redox chemistry and enlarges the gap between metallic and anionic states by constructing Li2ZrO3 slabs into Li2MnO3 domain in Li1.21Ni0.28Mn0.51O2 which fundamentally suppresses the voltage decay.