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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 Na2WO4 molten salt, electrolysis with Na2WO4–WO3 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 in situ Raman spectroscopy and activation strain model analysis. The results indicated that the molten salt system's behaviour, influenced by migration and polarization effects, led to increased formation of Na2W2O7 in the Na2WO4–WO3 molten salt, which has a lower decomposition voltage and subsequently accelerated the cathodic deposition of tungsten. We analyzed the mechanism of the effect of the electric field on the Na2W2O7 structure based on the bond strength and electron density. This research provides crucial theoretical support for the effect of electric field on tungsten in molten salt and demonstrates the feasibility of using machine learning-based DPMD methods in simulating tungsten-containing molten salt systems. [ABSTRACT FROM AUTHOR]

The electrolyte system of rechargeable aluminium-ion batteries (AIBs) is an urgent topic on account of the development in large-scale applications. In addition to the energy storage capabilities, enlargement of the electrolyte potential window is also a significant strategy for substantially boosting the energy density of the AIBs. To achieve these goals, here we demonstrate an Et3NHCl-based gel-polymer electrolyte with a wide electrochemical potential window for high-rate quasi-solid-state AIBs. Particularly, such a quasi-solid-state AIB presents stable specific capacities, maintaining around 90 mA h g−1 with long-term cycling under a high current density. More importantly, the Et3NHCl-based gel-polymer electrolyte here is not only favorable for increasing the cut-off charging potential, but also has various advantages, including a robust electrode–electrolyte interface, wide-temperature operating abilities and stability in a moist environment. Thus, the results may open a new avenue for low-cost and safe energy storage systems based on electrochemical technologies and applications. [ABSTRACT FROM AUTHOR]

A new Al-ion battery based on an affordable and nontoxic liquid electrolyte made from molten AlCl3/urea was assembled. As the cathode material, natural graphite shows two well-defined discharge voltage plateaus at about 1.9 and 1.5 V with a high specific capacity of 93 mA h g−1 and excellent coulombic efficiency (＞99%). The attractive capacity (about 78 mA h g−1) is retained even at a high current density of 1000 mA g−1. Moreover, no faster fading in capacity is observed after 500 cycles. This electrolyte could provide a new system for Al ion batteries, which can be used for large scale energy storage, owing to its cost advantages, high-rate capability and durability. [ABSTRACT FROM AUTHOR]

Affordable and scalable energy storage systems are necessary to mitigate the output fluctuation of an electrical power grid integrating intermittent renewable energy sources. Conventional battery technologies are unable to meet the demanding low-cost and long-life span requirements of a grid-scale application, although some of them demonstrated impressive high energy density and capacity. More recently, the prototype of an Al-ion battery has been developed using cheap electrode materials (Al and graphite) in an organic room-temperature ionic liquid electrolyte. Here we implement a different Al-ion battery in an inorganic molten salt electrolyte, which contains only an extremely low-cost and nonflammable sodium chloroaluminate melt working at 120 °C. Due to the superior ionic conductivity of the melt electrolyte and the enhanced Al-ion interaction/deintercalation dynamics at an elevated temperature of 120 °C, the battery delivered a discharge capacity of 190 mA h g−1 at a current density of 100 mA g−1 and showed an excellent cyclic performance even at an extremely high current density of 4000 mA g−1: 60 mA h g−1 capacity after 5000 cycles and 43 mA h g−1 capacity after 9000 cycles, with a coulombic efficiency constantly higher than 99%. The low-cost and safe characteristics, as well as the outstanding long-term cycling capability at high current densities allow the scale-up of this brand-new battery for large-scale energy storage applications. [ABSTRACT FROM AUTHOR]

The synthesis and electrochemical performance derived from NaHTi3O7 have been investigated for use as an anode material for sodium-ion batteries. NaHTi3O7 nanotubes were fabricated by a hydrothermal method. Galvanostatic charge/discharge measurements were performed in a voltage range of 0.01–2.5 V vs. Na+/Na at different current densities, using the as-prepared NaHTi3O7 nanotubes as the working electrode. Typically, the initial discharge and charge capacities of NaHTi3O7 nanotubes were 381.80 mA h g−1 and 242.82 mA h g−1, respectively, at a current density of 20 mA g−1, and still retained a high specific capacity of 105.32 mA h g−1 and 100.65 mA h g−1 after 100 cycles. The electrode also exhibits outstanding rate capability with a reversible capacity as high as 300.95 mA h g−1 and 209.10 mA h g−1 at current densities of 50 mA g−1 and 100 mA g−1, respectively. The excellent electrochemical stability and high specific capacity of these nanostructured materials have been attributed to the three-dimensional flower-like morphology of NaHTi3O7 nanotubes. All of the findings demonstrate that NaHTi3O7 nanotubes have steady cycling performance and environmental and cost friendliness for use in next generation secondary batteries of sodium-ion batteries. [ABSTRACT FROM AUTHOR]

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. A comparative study of amorphous and crystalline FePO4 has been carried out as cathode materials for Na-ion batteries. The present study not only reports a synthetic method which is facile, inexpensive, and scalable for mass production, but it also motivates further exploration of other amorphous materials for Na-ion batteries. [ABSTRACT FROM AUTHOR]

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 Na 2 WO 4 molten salt, electrolysis with Na 2 WO 4 -WO 3 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 in situ Raman spectroscopy and activation strain model analysis. The results indicated that the molten salt system's behaviour, influenced by migration and polarization effects, led to increased formation of Na 2 W 2 O 7 in the Na 2 WO 4 -WO 3 molten salt, which has a lower decomposition voltage and subsequently accelerated the cathodic deposition of tungsten. We analyzed the mechanism of the effect of the electric field on the Na 2 W 2 O 7 structure based on the bond strength and electron density. This research provides crucial theoretical support for the effect of electric field on tungsten in molten salt and demonstrates the feasibility of using machine learning-based DPMD methods in simulating tungsten-containing molten salt systems.

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. A comparative study of amorphous and crystalline FePO4 has been carried out as cathode materials for Na-ion batteries. The present study not only reports a synthetic method which is facile, inexpensive, and scalable for mass production, but it also motivates further exploration of other amorphous materials for Na-ion batteries.