Enhanced Thermal Stability and Conductivity of FeF3 Using Ni-Coated Carbon Composites: Application as High-Temperature Cathodes in Thermal Batteries.

Cathode active materials and conductive additives for thermal batteries operating at high temperatures have attracted research interest, with a particular focus on compounds offering high thermal stability. Recently, FeF3 has been proposed as a candidate for high-voltage cathode materials; however, its commercialization is hindered by its low conductivity. In this study, conductive additives, such as Ni-coated carbon composites (multi-walled carbon nanotubes (MWCNTs) and carbon black (CB)), were utilized to enhance the thermal stability and conductivity of FeF3. The incorporation of metal-carbon conductive additives in the FeF3 composite increased the thermal stability by more than 10 wt.% and ensured high capacity upon conductivity enhancement. The FeF3@Ni/MWCB 15 wt.% composite containing 30 wt.% Ni exhibited a discharge capacity of ∼86% of the theoretical capacity of 712 mAh/g. The use of Ni-coated carbon-based conductive additives will allow the application of FeF3 as an effective high-temperature cathode material for thermal batteries.

Correction: Massively synthesizable nickel-doped 1T-MoS2 nanosheet catalyst as an efficient tri-functional catalyst.

[This corrects the article DOI: 10.1039/D3RA03016D.].

Massively synthesizable nickel-doped 1T-MoS2 nanosheet catalyst as an efficient tri-functional catalyst.

In this study, a nickel (Ni)-doped 1T-MoS2 catalyst, an efficient tri-functional hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) catalyst, was massively synthesized at high pressure (over 15 bar). The morphology, crystal structure, and chemical and optical properties of the Ni-doped 1T-MoS2 nanosheet catalyst were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ring rotating disk electrodes (RRDE), and the OER/ORR properties were characterized using lithium-air cells. Our results confirmed that highly pure, uniform, monolayer Ni-doped 1T-MoS2 can be successfully prepared. The as-prepared catalysts exhibited excellent electrocatalytic activity for OER, HER, and ORR owing to the enhanced basal plane activity of Ni doping and formidable active edge sites resulting from the phase transition to a highly crystalline 1T structure from 2H and amorphous MoS2. Therefore, our study provides a massive and straightforward strategy to produce tri-functional catalysts.

Development of a low-melting-point eutectic salt and evaluation of its discharge performance for light weight thermal batteries.

This paper proposes low-melting-point eutectic salts containing RbCl as electrolytes for light weight thermal batteries. The handleability of the eutectic salts was remarkably improved for commercialisation. Their performance as thermal battery molten-salt electrolytes was verified using tests on a single cell and a 12-cell stacked battery.

Electrochemical properties of a lithium-impregnated metal foam anode (LIMFA FeCrAl) for molten salt thermal batteries.

Although numerous cathode materials with excellent properties have been developed for use in molten salt thermal batteries, similar progress is yet to be made with anode materials. Herein, a high-performance lithium-impregnated metal foam anode (LIMFA) is fabricated by impregnating molten lithium into a gold-coated iron-chrome-aluminium (FeCrAl) foam at 400 °C. A test cell employing the LIMFA FeCrAl anode exhibited a specific capacity of 2627 As g-1. For comparison, a cell with a conventional Li(Si) anode was also discharged, demonstrating a specific capacity of 982 As g-1. This significant improvement in performance can be attributed to the large amount (18 wt%) of lithium incorporated into the FeCrAl foam and the ability of the FeCrAl foam to absorb and immobilize molten lithium without adopting a cup system. For thermal batteries without a cup, the LIMFA FeCrAl provides the highest-reported specific capacity and a flat discharge voltage curve of molten lithium. After cell discharge, the FeCrAl foam exhibited no lithium leakage, surface damage, or structural collapse. Given these advantageous properties, in addition to its high specific capacity, LIMFA FeCrAl is expected to aid the development of thermal batteries with enhanced performance.

Hydrothermally synthesized homogeneous Ni-Mo-S structures on Ni-foam cathodes for thermal batteries.

Hydrothermally synthesized homogeneous structures based on Ni, Mo, and S on Ni metal foam cathodes (NiMoSs) were characterized electrochemically. A NiMoS-containing cell exhibited a much higher specific capacity of 1534 A s g-1 than an FeS2 cathode, owing to its homogeneous structure, demonstrating promise for thermal battery applications.

Photoelectrochemical overall water splitting with textured CuBi2O4 as a photocathode.

Nanotextured CuBi2O4 photocathodes have been developed for applications toward solar water splitting. Tailoring the CuBi2O4 photocathodes to yield a high photocurrent and a positively large onset potential demonstrates their applicability in a photoelectrochemical tandem cell for entirely solar-driven overall water splitting.