Roles of metal element substitutions from the bimetallic solid state electrolytes in lithium batteries

All-solid-state lithium batteries(ASSLBs),receiving extensive attentions and studies,exhibit better safety,environmental friendliness,stability,wider electrochemical stability window and higher energy density than traditionally liquid lithium batteries.In a variety of inorganic materials,with highly replaceable,the non-lithium metal elements emerge in endlessly and affect performances in diversiform ways.Due to facile preparation,convertible structures and excellent properties,the lithium-containing bimetallic granular materials are often applied as important components of electrolytes in lithium batteries.In this review,in terms of the properties of substituted elements,changing crystal structures,increasing vacancies or defects and improving the interfacial conductions,the roles of metal element substitutions of inorganic particles on the improvement of solid-state electrolytes are expounded.And the applications of substituted strategies in ASSLBs as the host of inorganic particles electrolytes and as fillers or modifications for composite electrolytes are also investigated and discussed.It also summarizes the current concerns and obstacles that need to be broken through,as well as provides a basis guide for the selection and optimization of inorganic particles.

A New Sandwiched-type Polyoxotungstate Containing {Cd_4} Transition-metal Cluster:Synthesis,Structure and Luminescent Property

A new sandwiched polyoxometalate [HK11Cd4Cl2（PW9034）2]·18H2O （1）, incor- porating a unique hybrid tetranuclear cadmium cluster （abbreviated to {Cd4}） with two trivacant polyanions [B-α-PW9O34]9-, has been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectroscopy, UV-vis, and single-crystal X-ray diffraction analysis. Crystal data for 1： monoclinic, space group C2/c, a = 19.2997（4）, b = 13.8014（3）, c = 31.9819（8） A, β = 102.764（2）°, V= 8308.3（3） A3, Z = 4, P2O86Cl2K11Cd4W18H37, Mr = 5735.13, Dc = 4.584 mg-mm-3, F（000） = 10084, μ = 26.579 mm-1, the final R = 0.0378 and wR = 0.0989 for 6558 observed reflections （I〉 2σ（I））. X-ray crystallographic study shows that the molecular structure of 1 contains four cadmium atoms. Two CdO6 distorted octahedra and two CdOsC1 distorted octahedra combine with each other in turn via edge-sharing, resulting in a regular rhomb-like cluster sandwiched between two {B-a-PW9034} units. Further, the sandwich-type polyoxoanions were connected by K＋ ions to form a complicated 3-D open-framework through connecting with each terminal O atom of the [Cd4C12（PW9O34）2]12- polyoxoanions. In addition, compound 1 exhibits photoluminescence property at room temperature and the band gap can be assessed at 3.25 eV.

Competitive Occupying of Fe^3+ and Co^3+ Ions into the Lattice B-Sites of Perovskite Crystalline Structure

Perovskite-type oxide has a general formula ABO3. Both the lattice A- and lattice B-sites can be occupied by two kinds of metallic ions, forming substituted perovskites such as La（1-x）SrxCoO3-d and LaFexCo（1-x）O3. In the present work, we aim to investigate competitive occupying of Fe（3＋） and Co（3＋） ions into the lattice B-sites of perovskite LaFexCo（1-x）O3 formed under the condition of excess feeding of Fe（3＋） and Co（2＋） ions relative to the La（3＋） ions. For this purpose, standard curve of normalized cell volumes（NCVs） of a defined series of perovskites LaFexCo（1-x）O3 versus the x values was plotted. Lattice occupancy of Fe（3＋） ions at the B-sites of the perovskite LaFexCo（1-x）O3 was then determined from the standard curve. It is proved that Fe（3＋） ions were capable of occupying preferentially into the lattice B-sites of the perovskite crystalline structure.

Visible light responsive photocatalysts developed by substitution with metal cations aiming at artificial photosynthesis

To solve resource,energy,and environmental issues,development of sustainable clean energy system is strongly required.In recent years,hydrogen has been paid much attention to as a clean energy.Solar hydrogen production by water splitting using a photocatalyst as artificial photosynthesis is a promising method to solve these issues.Efficient utilization of visible light comprised of solar light is essential for practical use.Three strategies,i.e.,doping,control of valence band,and formation of solid solution are often utilized as the useful methods to develop visible light responsive photocatalysts.This minireview introduces the recent work on visible-light-driven photocatalysts developed by substitution with metal cations of those strategies.

Phase transition of SrCo_(0.9)Fe_(0.1)O_(3) electrocatalysts and their effects on oxygen evolution reaction

Complex metal oxide has emerged as an important class of electrocatalyst for oxygen evolution reaction(OER)because of its flexibility in the crystal phase and relative ease in the control of defect structures.While different crystalline phases and solid structures may be produced from the same reactant precursors,their phase transitions and OER performances are not well understood.In this work,we present the preparation of different phases of SrCo_(0.9)Fe_(0.1)O_(3-δ)(nominal ratio)solids using a sol-gel method and the structure-catalytic property relationship of both crystalline and amorphous structures formed at different temperatures.We observed as synthetic temperature increased,phase and composition transitions occurred from the amorphous phase to strontium carbonate and cobalt oxide,to oxygen-deficient perovskite,and finally to perovskite.The OER activity depended highly on crystal structures.The oxygen-deficient perovskite prepared at 750℃ exhibited the highest catalytic activity,while the perovskite showed the lowest activity.X-ray photoelectron spectroscopy analysis reveals the change of oxidation state occurred during the phase transition.This work provides a useful guideline for the design of OER electrocatalysts through controlling the crystal structures and defects in complex metal oxides,such as perovskite.