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Senast publicerade

Optimized Synthesis of Multi Metal Prussian Blue Analogues Towards Stable Sodium-Ion Battery Cathode
(2026) Mohan, Prateek
Sodium-ion batteries are increasingly considered a viable alternative to lithium-ion systems for large-scale (stationary) energy storage due to the abundance and low cost of sodium. Among potential cathode materials, Prussian Blue Analogues (PBAs) offer fast sodium-ion diffusion and high operating voltages but often suffer from structural instability and capacity fading during long-term cycling. In this study, multi-metal Prussian Blue Analogues are developed to overcome these limitations by stabilising the framework and enhancing electrochemical performance through synergistic interactions between multiple transition metals. The materials were synthesised using controlled co-precipitation and hydrothermal methods, enabling precise control over composition, morphology, and defect concentration. Structural and electrochemical characterisation using X-ray diffraction, scanning electron microscopy, cyclic voltammetry, galvanostatic charge–discharge testing, and electrochemical impedance spectroscopy demonstrates improved crystallinity, reduced polarisation, enhanced rate capability, and superior cycling stability compared with single-metal PBAs. The improved performance is attributed to enhanced redox activity and improved structural integrity during repeated sodium insertion and extraction. These results highlight multi-metal Prussian Blue Analogues as promising cathode materials for scalable and durable sodium-ion batteries intended for stationary and grid-level energy storage applications.
Enhancing the Lithium-Ion Battery Performance of Commercial Micron-sized Silicon Particles using Graphene
(2026) Namagondlu Kishan, Preeth
Silicon is known to be one of the most promising anode material for future-generation lithium-ion batteries, thanks to its theoretical specific capacity of approximately 3579 mAh/g. Nonetheless, the use of silicon anodes is hampered in practical devices owing to their large volume expansion during lithiation, the instability of the solid electrolyte interface, capacity decay, and poor rechargeability. Specifically, micron-sized commercial-grade silicon particles exhibit drastic pulverization, along with the loss of electrical contact, during the cycling process. This thesis attempts to improve the electrochemical properties of commercial micron-sized silicon materials by thick graphene coating. A comprehensive strategy included the size reduction of the materials via ball mill processing, the introduction of functional groups through APTES silanization, the deposition of graphene oxide, and finally, chemical reduction of the resultant material on the surface of the silicon materials to create a graphene layer. The optimized ball-milled, uniformly graphene-coated silicon electrodes revealed a remarkably high discharge capacity of about 3400 mAhg-1. Significantly improved stability was also observed, retaining a discharge capacity of 1600-1800 mAhg-1 after 25 cycles in a designed half-cell. However, the unmodified silicon electrodes, along with the non-uniformly modified samples, suffered from a sharp decrease in discharge capacities below the 500 mAhg-1mark. These findings prove the effectiveness of homogeneous graphitic coatings, together with size reduction, in reducing the volume expansion of silicon and preserving electrical connections. This work presents a feasible, affordable method to enhance the performance of commercial, micron-sized Si anode materials, filling the technological gap between the lab scale and commercial Li-ion batteries (LIB).
Sustainability assessment of timber bridge design - An iterative study of a conceptual timber bridge design using life cycle and Life Cycle Costing Assessment
(2025) Holmström, Olivia; Högberg, Anna
Today, the building and infrastructure sector is a significant contributor to global green house gas emissions, with bridges often designed using materials with high embodied carbon, such as steel and concrete. Timber bridges present a renewable, carbon-storing alternative that can significantly reduce environmental impact. However, the demand remains low due to negative perceptions about durability and maintenance. This thesis aims to compare the environmental and economic performance of timber and steel components in bridge design, identifying key factors that influence sustainability and cost across the entire life cycle. Developed with Timber Bridges Specialist AB, the project follows an early-stage design process for an ongoing project using its context as a framework. The work was carried out using FEM-Design, where the bridge was structurally modeled and dimensioned, followed by iterative Life Cycle Assessment (LCA) and Life Cycle Cost Assessment (LCCA) to evaluate alternative deck and railing configurations. The study also assessed the substitution of pressure-impregnated timber with heat-treated timber to explore potential sustainability improvement. The results show that timber components, particularly in railings, significantly lower climate impact and cost compared to steel. Efficient use of steel, such as trapezoidal corrugated sheets, can be a good alternative due to its efficient material use. Overall, timber outperforms steel both when it comes to environmental impact and cost, especially when carbon storage is considered. The findings emphasize that optimizing material selection and material efficiency for each bridge component can improve sustainability and cost-effectiveness, promoting broader adoption of timber bridges in future projects.
Loudspeaker–Room Response Equalization Using a Smartphone Microphone
(2025) Hanus, Jan
The thesis investigates the topic of loudspeaker-room response equalization (LRRE) and tries to find a suitable method for integration into a pair of compact studio monitors. LRRE is a method for improving a loudspeaker system’s performance in a room by measuring an impulse response in the listening position, based on which compensation filters are computed and applied to the loudspeaker system. The aim is also to assess whether such impulse response measurements can be performed using today’s smartphones with their built-in microphone. The whole procedure, from impulse response measurement to the computation of the compensation filter, is described, and techniques that correct only the magnitude response (minimum-phase compensation) and those correcting both the magnitude and phase responses (mixed-phase compensation) are compared. Three particular equalization functions are implemented in Python: a minimum-phase FIR filter, a mixed-phase FIR filter obtained by the x-filtered normalized least mean square algorithm, and a minimum-phase IIR filter comprising a cascade of biquad peak filters. It is found that the latter performs the best and is the most suitable option for integration into compact studio monitors. A theoretical performance of a smartphone used as the measurement device is dis cussed by presenting the expected behaviour of the present MEMS microphone, and the application of digital signal processing by the manufacturer. The actual behaviour is then evaluated by measuring the frequency responses and sensitivi ties of 30 smartphones in an anechoic chamber and assessing their SNR. 84% of the tested models emerged as suitable for measuring the loudspeaker-room impulse response
Water we gonna do with all this waste
(2025) Rosenberg, Eleonora
This master’s thesis explores how Gothenburg can strengthen its resilience to flooding by integrating circular economy principles into urban design. The study investigates how recycled construction waste, such as excavated clay, crushed brick, concrete, dredged sediments and etc. can be repurposed into functional materials for flood prevention infrastructure. It responds to the growing urgency of climate change impacts, including rising sea levels, increased precipitation, groundwater pressure, and extreme weather events such as cloudbursts. These factors are compounded by unsustainable urban development and inefficient waste management, especially in flood-prone areas like the Göta river (hereafter referred to as Göta älv) corridor. The research examines multiple flood risks affecting Gothenburg, including fluvial, pluvial, and coastal flooding, while analyzing the city’s existing flood mitigation frameworks. It identifies opportunities to enhance urban water retention, filtration, and controlled discharge using reclaimed materials within blue-green infrastructure systems. Drawing on principles of sponge city design, the thesis explores how urban surfaces can be transformed from impermeable zones into absorbent, biologically active systems that not only mitigate flooding but also enrich public space. The outcome is a design proposal for a specific site in Gothenburg, using adaptable strategies that integrate waste reuse with climate adaptive planning. The design utilizes porous layers made from recycled construction waste to support vegetation, slow runoff, and improve water quality before controlled discharge into receiving bodies. In doing so, the proposal rethinks flood protection not as a singular defense mechanism, but as a layered system of ecological and material functions. This thesis contributes to the growing discourse on sustainable urban transformation by demonstrating that construction waste, when treated as a resource, offers both environmental and economic value. By merging flood resilience with circular material flows, the project promotes an urban design approach that is adaptable, regenerative, and aligned with Sweden’s climate goals. It provides a flexible model that could be applied in other urban areas facing similar challenges, emphasizing that resilient cities can be built through both design innovation and material responsibility. This thesis will explore the following research question: How can recycled construction waste be reimagined as a resource for sustainable water management strategies in Gothenburg?