Liquid metal batteries have been introduced as promising option to address the needs for new energy storage technologies. Currently, batteries based on sodium and zinc are under development and a favorable option due to their high theoretical cell potential, readily abundant materials, and cost-advantages. Nevertheless, they face the problem of self-discharge, which makes it inevitable to understand fluid dynamics in the whole cell. Motivated by that, several types of fluid mechanic instabilities in Na-Zn liquid metal batteries are identified and discussed here. On the one hand they can jeopardize secure operation, but on the other hand they can also improve mixing and increase the cell efficiency. In doing so, realistic cell as well as operation parameters are included and dimensionless numbers for identifying critical conditions are presented. The phenomena with highest significance for the discussed batteries are solutal convection, swirling flow, electrocapillary Marangoni convection, and droplet formation. Still, many open research questions remain and we aim at motivating researchers to dig deeper into some of these topics to contribute to an improved cell design and performance.

Identifying optimum anode baking level and mixing temperature are important when producing high quality anodes. The effect of varying mixing temperature and baking level were investigated in terms of the resulting apparent anode density, specific electrical resistivity (SER), air permeability, coefficient of thermal expansion (CTE), air reactivity, and CO₂ reactivity. Six pilot-scale anodes were prepared at Hydro Aluminium using a single source petroleum coke and <2 mm coke fractions. A coal tar pitch was used with Mettler softening point of 119.1 °C. The aggregate was mixed at 150 °C or 210 °C and baked to a low, medium, or high baking level. A 2² full-factorial design analysis was performed to determine the response of the analyzed properties to the applied mixing and baking temperature. Apparent density, SER, and air permeability were found to be highly dependent on mixing temperature. Apparent density and SER were also slightly affected by baking level. CTE was found to be independent of both baking level and mixing temperature. Air reactivity was found to be mainly dependent on baking level, while CO₂ reactivity was dependent on both mixing temperature and baking level.

The environmental footprint of the aluminum industry is affected by greenhouse gas emissions and the amount of waste generated. Spent potlining (SPL) has traditionally been deposited, but increasing scrutiny is put to this practice. The cost of deposit is also increasing. First cut SPL is the carbon rich part and are the remaining cathode at end-of-life of an aluminum cell. A method for cleaning the first cut SPL is proposed which involves high temperature and low-pressure treatment for removal of fluoride-rich electrolyte remains. This way the carbon rich part of the SPL can become a product which can be reused or secondly used as an energy source, instead of being deposited. 5–19 kg of SPL has been treated for four hours in a furnace at low pressure and high temperature, and a post-treatment carbon purity up to 98 wt pct was found. The electrolyte condensate mainly consists of NaF og Na₃AlF₆. An LCA study on the process related to Norwegian aluminum smelters has been performed and the distance to the SPL treatment plant, the energy used during treatment and the SPL pre-processing, was found to affect the sustainability of such an industrial process the most.

During production of aluminum in Hall-Héroult cells, carbon anodes electrochemically oxidize to form mainly CO₂. The CO₂ bubbles block the anode working surface during growth and coalescence, leading to cell voltage loss and voltage oscillations. Lower grade isotropic petroleum cokes are currently being introduced to anodes worldwide, but little is known about effects of coke quality on the unavoidable voltage losses linked to bubble formation. To investigate this, a pilot carbon anode series was made with various blended ratios of isotropic to anisotropic coke. The anodes were characterized with respect to voltage oscillations related to bubble formation and release, wettability toward electrolyte and surface roughness before and after electrolysis. Results showed that voltage noise caused by gas bubbles was reduced for anodes containing isotropic coke. For blended anodes of isotropic and anisotropic coke, the potential oscillation amplitude was reduced by ∼0.19 V compared to a 100% anisotropic coke anode. The percentage of the anode surface screened by gas bubbles was also reduced as isotropic coke was introduced. Increased wettability between electrolyte and two anodes containing isotropic coke was observed after anode polarization. The reduced bubble screening on the anode surface was attributed to better wetting between anode and electrolyte.