Effect of electric fields on tungsten distribution in NaWO-WO molten salt.

Tungsten coatings have unique properties such as high melting points and hardness and are widely used in the nuclear fusion and aviation fields. In experiments, compared to pure NaWO molten salt, electrolysis with NaWO-WO molten salt results in a lower deposition voltage. Herein, an investigation combining experimental and computational approaches was conducted, involving molecular dynamics simulations with deep learning, high-temperature Raman spectroscopy and activation strain model analysis.

Operando probing and adjusting of the complicated electrode process of multivalent metals at extreme temperature.

Nearly half of the elements in the periodic table are extracted, refined, or plated using electrodeposition in high-temperature melts. However, operando observations and tuning of the electrodeposition process during realistic electrolysis operations are extremely difficult due to severe reaction conditions and complicated electrolytic cell, which makes the improvement of the process very blind and inefficient. Here, we developed a multipurpose operando high-temperature electrochemical instrument that combines operando Raman microspectroscopy analysis, optical microscopy imaging, and a tunable magnetic field.

Ultra-High Temperature Molten Oxide Electrochemistry.

Recently, the ultra-high temperature electrochemistry (UTE, about >1000 °C) has emerged, which represents an exploration to extend the temperature limit of human technology in electrochemical engineering. UTE has far-reaching impact on revolutionary low-carbon metal extraction and the in situ production of oxygen for deep-space exploration. It is hence of urgency to systematically summarize the development of UTE.

A 4D x-ray computer microtomography for high-temperature electrochemistry.

High-temperature electrochemistry is widely used in many fields. However, real-time observations and an in-depth understanding of the inside evolution of this system from an experimental perspective remain limited because of harsh reaction conditions and multiphysics fields. Here, we tackled this challenge with a high-temperature electrolysis facility developed in-house.

Stable Quasi-Solid-State Aluminum Batteries.

Nonaqueous rechargeable aluminum batteries (RABs) of low cost and high safety are promising for next-generation energy storage. With the presence of ionic liquid (IL) electrolytes, their high moisture sensitivity and poor stability would lead to critical issues in liquid RABs, including undesirable gas production, irreversible activity loss, and an unstable electrode interface, undermining the operation stability. To address such issues, herein, a stable quasi-solid-state electrolyte is developed via encapsulating a small amount of an IL into a metal-organic framework, which not only protects the IL from moisture, but creates sufficient ionic transport network between the active materials and the electrolyte.

Quantificational 4D Visualization of Industrial Electrodeposition.

Electrodeposition is a fundamental technology in modern society and has been widely used in metal plating and extraction, etc. However, extreme reaction conditions, including wide operation temperature ranges and corrosive media (molten salt/oxide systems as a particular example), inhibit direct in situ observation of the electrodeposition process. To visualize the electrode kinetics in such "black box," X-ray tomography is employed to monitor the electrochemical processes and three-dimensional (3D) evolution of morphology.

Nonmetal Current Collectors: The Key Component for High-Energy-Density Aluminum Batteries.

As one of the emerging safe energy-storage devices with high energy-to-cost ratio, nonaqueous aluminum batteries with enhanced energy density are intensively pursued by researchers. Although significant progress has been made on positive electrode materials, the effective energy density of aluminum batteries is still limited by the presence of high-density refractory metal current collectors, which are known to be electrochemically inert in highly acidic ionic-liquid electrolytes. To address such critical issues, here, a novel low-density (<2 g cm ) nonmetal current collector is presented, which uses poly(ethylene terephthalate) (PET) substrates coated with indium tin oxide (ITO), with the purpose of significantly reducing the ratio of nonactive components in the electrodes.

Stable Interface between a NaCl-AlCl Melt and a Liquid Ga Negative Electrode for a Long-Life Stationary Al-Ion Energy Storage Battery.

Intermediate temperature NaCl-AlCl-based Al-ion batteries are considered as a promising stationary energy storage system due to their low cost, high safety, etc. However, such a cheap electrolyte has a critical feature, i.e.

Rechargeable Nickel Telluride/Aluminum Batteries with High Capacity and Enhanced Cycling Performance.

Rechargeable aluminum-ion batteries (AIBs) possess significant advantages of high energy density, safety performance, and abundant natural resources, making them one of the desirable next-generation substitutes for lithium battery systems. However, the poor reversibility, short lifespan, and low capacity of positive materials have limited its practical applications. In comparison with semiconductors, the metallic nickel telluride (NiTe) alloy with enhanced electrical conductivity and fast electron transmission is a more favorable electrode material that could significantly decrease the kinetic barrier during battery operation for energy storage.

Production of Ti-Fe alloys molten oxide electrolysis at a liquid iron cathode.

This work studies the direct electrochemical preparation of Ti-Fe alloys through molten oxide electrolysis (MOE) at a liquid iron cathode. Cyclic voltammetry and potentiostatic electrolysis have been employed to study the cathodic process of titanium ions. The results show that cathodic behavior happens during the negative sweep at a potential range from -0.

A Novel Ultrafast Rechargeable Multi-Ions Battery.

An ultrafast rechargeable multi-ions battery is presented, in which multi-ions can electrochemically intercalate into graphite layers, exhibiting a high reversible discharge capacity of ≈100 mAh g and a Coulombic efficiency of ≈99% over hundreds of cycles at a high current density. The results may open up a new paradigm for multi-ions-based electrochemical battery technologies and applications.

A rechargeable Al-ion battery: Al/molten AlCl-urea/graphite.

A new Al-ion battery based on an affordable and nontoxic liquid electrolyte made from molten AlCl/urea was assembled. As the cathode material, natural graphite shows two well-defined discharge voltage plateaus at about 1.9 and 1.

Direct Conversion of Greenhouse Gas CO2 into Graphene via Molten Salts Electrolysis.

Producing graphene through the electrochemical reduction of CO2 remains a great challenge, which requires precise control of the reaction kinetics, such as diffusivities of multiple ions, solubility of various gases, and the nucleation/growth of carbon on a surface. Here, graphene was successfully created from the greenhouse gas CO2 using molten salts. The results showed that CO2 could be effectively fixed by oxygen ions in CaCl2-NaCl-CaO melts to form carbonate ions, and subsequently electrochemically split into graphene on a stainless steel cathode; O2 gas was produced at the RuO2-TiO2 inert anode.

A sodium ion intercalation material: a comparative study of amorphous and crystalline FePO4.

Due to their low cost, high abundance and eco-friendly features, Na-ion batteries are becoming alternative choices for rechargeable batteries, especially in large scale applications. Generally, the well-crystallized materials have many advantages over amorphous materials, such as long cycle life, high rate performance and other electrochemical properties. However, the amorphous FePO4 we report here exhibits outstanding cycling stability and rate performance which are derived from its amorphous nature and wafer-like porous morphology.