Superkondensatorer är energilagringsenheter som har uppmärksammats mer under det senaste decenniet. Några av de fördelar som dessa enheter har varit är lagring av hög effekttäthet, förlängda livscykler och snabba laddnings- och urladdningstider. Dock är superkondensatorer fortfarande begränsade i energitäthet i jämförelse med batterier. För att få högre effekt och energitäthet är en asymmetrisk hybrid superkondensator ett bra alternativ. Denna enhet består av en kolbaserad elektrod för icke-faradaiska reaktioner och en kolelektrod kombinerad med metalloxider för redoxreaktioner. Materialvalet spelar en avgörande roll för förmågan en hybrid asymmetrisk superkondensator ska ha. I denna studie undersöks fyra olika kommersiella kol. Den specifika ytan, porstorlekarna och morfologin jämförs. Dessutom syntetiseras metalloxidernanopartiklar MnO2 och kristallstrukturen undersöks. Därtill beläggs MnO2-partiklarna på de fyra kolen och tillväxten av dessa undersöks. Slutligen analyseras interaktionen mellan jonvätskan 1-butyl-3-metylimidazoliumtetrafluorborat (BMIM[BF4]) som en elektrolyt och de olika kolen. / Supercapacitors are energy storage devices that have drawn attention for the past decade. Some of the advantages of these devices are higher power density storage, extended life cycles, and fast charge and discharge times. However, supercapacitors are still limited in energy density compared to batteries. To obtain higher power and energy densities, a hybrid asymmetric supercapacitor is a good alternative. This device consists of one carbon-based electrode for non-faradaic reactions, and one carbon electrode combined with metal oxides for redox reactions. The material choice is important for the capability of a hybrid asymmetric supercapacitor. In this study, four different commercial carbons are investigated. The specific surface area, pore sizes, and morphology are compared. In addition, metal oxide nanoparticles MnO2 are synthesised, and crystal structure is investigated. Furthermore, the MnO2 particles are deposited on the four carbons and the growth of those is studied. Finally, the interaction between ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM[BF4]) as an electrolyte and the different carbons is studied.

Modified nanocellulose have distinctive qualities and have drawn a lot of interest from a variety of fields. It is a natural, sustainable product that is manufactured from plant-based materials like wood and other renewable resources. It is also biodegradable. It is a possible material for battery separators because of its great mechanical strength, flexibility, and ability to create a stable and consistent membrane. Due to the cost of using it as a membrane, it has been investigated in this work to see if it can be coated onto a substrate and used as battery separator. In this work sulfonated cellulose nanofibrils (SCNF) has been used to be coated on kraft paper and inkjet paper using a rod coater. Parameters like concentration, thickness and substrates have been varied in this experiment. Viscosity was measured using Brookfield instrument to measure the viscosity for 0,5% SCNF and 1,5% SCNF. The coating was carried out using a rod coater and varying between two rods to influence the thickness, the coating used concentrations of 0,5% SCNF and 1,5% SCNF and two different substrates, kraft paper and inkjet paper. Thickness was determined to study the effect of the variation in rod. The mechanical strength was tested on the coated paper substrates and compared the results to the noncoated substrates as reference, the mechanical strength showed an improvement with the coated SCNF substrates. Permeance through the Gurley method was studied in order to understand how the coated substrates behaves compared to the noncoated. Contact angle was determined as well to understand the wettability of the coated substrates and how they would behave as separators in zinc ion batteries. The contact angle decreased with increasing concentration of the SCNF which is a result of the sulfonate groups. Cross sections were analyzed using SEM to study the influence of the coating to the substrates. Ionic conductivity was also tested to evaluate the possibility of the coated substrates as separators.

Fuel cells play a key role in implementing hydrogen as alternative fuel to eliminate CO2-emissions and their performance is largely dependent on the contact resistance of the surface of bipolar plates. For stainless steel bipolar plates titanium carbonitride coatings were suggested for modifying surface properties and thereby reducing contact resistance while maintaining mechanical strength. This study analysed Ti(C,N) coatings with different carbon content in terms of composition, microstructure chemical bonding and contact resistance. The films were deposited either by reactive co-sputtering from a titanium and a graphite target under nitrogen flow or by co-reactive sputtering from a titanium target under flow of nitrogen and methane. It was found that an increase in carbon content results in a nanocomposite of Ti(C,N) and an amorphous carbon (a-C) matrix leading to nanocrystalline films with a smooth surface. Analysing the amount of a-C as a functions of overall carbon content, it is observed that carbon is more effectively incorporated into carbonitride grains when using methane gas as a carbon source. Furthermore, the contact resistance of the titanium carbonitride coatings was found to be lowest (below 10 mΩ) for a small amount of a-C phase and overall lower than that of carbide and nitride reference samples. Therefore, titanium carbonitrides are a promising coating material for electrical contact applications such as fuel cells.

The pursuit of sustainable and high-performance materials is of utmost significance in driving the progress of battery technologies. Solid-state technology represents a promising avenue for the development of batteries with improved sustainability and performance. In this context, the present study delves into the examination of composition and the substitution of oxygen with nitrogen within the 50Li2O-xSiO2-(50-x)P2O5 glass system, specifically as applied to Solid-State electrolytes. The objective is to evaluate the influence of these factors on the electrical properties of the glass and their potential implications for Solid-State battery technology. The glass matrix was obtained through the melt-quenching technique, followed by comprehensive characterization using electrochemical impedance spectroscopy. The influence of varying silica content on the conductivity of the glass was investigated. This led to the selection of the glass system with the highest conductivity for further experiments involving nitridation. Subsequent experiments on nitridation aimed to explore the impact of nitrogen incorporation on the conductivity of the glass. By systematically varying the nitrogen content at different temperatures, the study sought to elucidate the relationship between nitrogen content and the resulting increase in glass conductivity.    The study reveals a noteworthy finding regarding the impact of nitrogen content on the conductivity of the glass. Specifically, when the nitrogen content was increased, the conductivity increased. In the case of a similar glass composition in pellet form, the conductivity at room temperature increased from Log σ = -8,009 (for glass without nitrogen) to Log σ = -6,951 (for nitrided glass). Additionally, the introduction of nitrogen into the glass resulted in a decrease in activation energy, being reduced from 0,66 eV (for oxide glass) to 0,60 eV (for oxynitride glass). These results indicate a clear correlation between increased nitrogen content and enhanced electrical properties of the investigated glasses; although obtaining a homogeneous bulk glass after nitridation was not feasible. Therefore, the nitrided samples were pelletized and sintered under different thermal conditions to obtain characterizable samples. The findings suggest that nitrogen substitution could be a promising approach for enhancing the electrical properties of the glasses of the title system of composition. Further investigation is required to optimize the process and achieve homogeneous bulk oxynitride glass.

Forskningsområdet för bärbar elektronik är fortfarande relativt ungt och det finns ett stort behov av utveckling av nya material inom området. Olika typer av kompositer är mycket intressanta och de ska uppvisa såväl hög hållfasthet som goda ledande egenskaper. I detta avseende är silkes fibroin och MXene mycket intressanta utgångsmaterial eftersom silkestrådarna kan ge en struktur med god jonledningsförmåga och god flexibilitet och MXene kan bidra med hög styvhet och god elektrisk ledningsförmåga. Med detta som bakgrund beslöts att undersöka om kompositer av silkestrådar och MXene kan användas i kompositer som kan användas i bärbar elektronik. 3 olika typer av hydrogeler studerades och de innehöll silkes fibroin med 0, 1 och 5% MXene. De egenskaper som utvärderades var struktur, mekaniska egenskaper, stabilitet i vatten, bionedbrytbarhet och både statisk och dynamisk ledningsförmåga. Resultaten visar att de tillverkade nanokompositerna har lovande förutsättningar inom området eftersom en kombination av silkes fibroin med 5 % MXene har god stabilitet, konduktivitet och en hög och stabil Gauge-faktor. / As the research area of wearable electronics is still relatively new, material science with this focus opens plenty of unexplored fields. That is why a study characterizing the unexplored composite system of silk fibroin and MXene (Silk/MXene) was conducted. These two biocompatible materials are complementary with regard to the requirements for wearable electronics materials. Silk fibroin dispose an ionic conductivity and solid flexibility, while MXene brings mechanical strength and significant increase of electrical conductivity. The reinforced hydrogel materials were studied at two concentrations of fillers, 1% and 5% and compared to pristine silk fibroin. All three materials were studied from the point of view of their structure, mechanical properties, behaviour in aqueous environment, biodegradability and electrical conductivity, both static and dynamic. Nanocomposite systems of silk fibroin and MXene have shown a potential for being used in the intended application area, as Silk/MXene 5% film displays good stability, conductivity with high andstable Gauge factor.

With the growing impact of climate change on both political decisions and how companies develop their products, it is increasingly important to find environmentally friendly alternatives to fossil-based materials. One of the more interesting materials in this respect is cellulose, which is the world's most naturally occurring polymer and can be used in a variety of applications. One way to modify the fibers and to change their properties is to use a method called Layer-by-Layer (LbL) treatment where two polymers of opposite charge are alternately adsorbed to the fiber surface. Another possibility is to oxidize the cellulose in the fibers to obtain a higher charge. This means that the fibers can adsorb a higher amount of cationic additives and that the fibers swell more which means that they are plasticized and can create stronger joints between the fiber surfaces in the dry state, which results in stronger dry fiber networks. However, wood-based fibers are small and inhomogeneous, both chemically and morphologically, which means that it is necessary to use model systems to be able to clarify, in detail, how treated and untreated surfaces interact with each other at a molecular level. One model system that can be used to investigate how cellulose fibers are affected by coating using the LbL method is to use spherical beads made from regenerated cellulose. In the present work, these beads were treated with polyallylamine hydrochloride (PAH) and hylauronic acid (HA) as well as with PAH and alginate (Alg) before being allowed to dry together and then subjected to tensile testing to clarify the adhesion between the surfaces. The beads were treated with five and ten bi-layers of these polymers, respectively, and then dried together on an AKD-coated surface, to avoid adhesion to the underlying surface, to examine the adhesion between the beads. The adhesion increased when treated with LbL and became higher upon adsorption of multiple layers of polyelectrolytes and the Alg / PAH system showed the greatest increase. Ten-layer samples of Alg / PAH were also tested after a solution of calcium chloride was added during drying, resulting in poorer adhesion between the beads. / Med klimatfrågans växande inverkan på både politiska beslut och hur företagen utvecklar sina produkter så läggs det allt större vikt vid att hitta miljövänliga alternativ till fossilbaserade material. Ett av de mer intressanta materialen är cellulosa vilket är världens mest naturligt förekommande polymer och som kan användas i en rad olika tillämpningar. Ett sätt att modifiera fibrerna och att ändra deras egenskaper är att använda sig av en metod som kalls Layer-by-layer (LbL) behandling där två polymerer mot motsatt laddning växelvis adsorberas till fiberytan. En annan möjlighet är att oxidera cellulosan i fibrerna så att de erhåller de en högre laddning. Detta innebär dels att fibrerna kan adsorbera en högre mängd katjoniska tillsatskemikalier samt att fibrerna sväller mera vilket innebär att de plasticeras och kan skapa starkare fogar mellan fiberytorna i torrt tillstånd vilket resulterar i starkare torra fibernätverk. Vedbaserade fibrer är dock små och inhomogena såväl kemiskt som morfologiskt vilket innebär att det är nödvändigt att använda modellsystem för att kunna klarlägga, i detalj, hur behandlade och icke behandlade ytor växelverkar med varandra på en molekylär nivå. Ett modellsystem som kan användas för att undersöka hur cellulosafibrer påverkas av att beläggas med hjälp av LbL metoden är att använda sig av sfäriska kulor tillverkade från regenererad cellulosa. I föreliggande arbete behandlades dessa kulor med polyallylaminhydroklorid (PAH) och hylauronsyra (HA) samt med PAH och alginat (Alg) innan de tilläts torka ihop och därefter utsattes för dragprovning för att klarlägga adhesionen mellan ytorna. Kulorna behandlades med fem respektive tio bilager av dessa polymerer och torkades sedan ihop på en AKD-belagd yta, för att undvika adhesion till den underliggande ytan, för att undersöka adhesionen mellan kulorna. Adhesionen ökade när de behandlades med LbL och blev högre vid adsorption av flera lager polyelektrolyter och systemet med Alg/PAH resulterade i den största ökningen. Prover med tio lager av Alg/PAH testades även efter att en lösning av kalciumklorid tillsattes under torkningen vilket resulterade i en sämre adhesion mellan kulorna.

In recent years, nanostructured materials incorporated with inorganic particles and polymers have attracted attention for simultaneous multifunctional biomedical applications. This thesis summarized three works, which are preparation of mesoporous silica coated superparamagnetic iron oxide (Fe3O4@mSiO2) nanoparticles (NPs) as magnetic resonance imaging T2 contrast agents, polymer grafted Fe3O4@mSiO2 NPs response to temperature change, synthesis and biocompatibility evaluation of high aspect ratio (AR) gold nanorods. Monodisperse Fe3O4@mSiO2 NPs have been prepared through a sol-gel process. The coating thickness and particle sizes can be precisely controlled by varying the synthesis parameters. Impact of surface coatings on magnetometric and relaxometric properties of Fe3O4 NPs is studied. The efficiency of these contrast agents, evaluated by MR relaxivities ratio (r2/r1), is much higher than that of the commercial ones. This coating-thickness dependent relaxation behavior is explained due to the effects of mSiO2 coatings on water exclusion. Multifunctional core-shell composite NPs have been developed by growing thermo-sensitive poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAAm-co-AAm)) on Fe3O4@mSiO2 NPs through free radical polymerization. Their phase transition behavior is studied, and their lower critical solution temperature (LCST) can be subtly tuned from ca. 34 to ca. 42 °C, suitable for further in vivo applications. A seedless surfactant-mediated protocol has been applied for synthesis of high AR gold nanorods with the additive of HNO3. A growth mechanism based on the effect of nitrate ions on surfactant micelle elongation and Ostwald ripening process is proposed. The biocompatibility of high AR nanorods was evaluated on primary human monocyte derived dendritic cells (MDDCs). Their minor effects on viability and immune regulatory markers support further development for medical applications. / QC 20110701

This report aims to study the degradation of poly(trimethylene carbonate) (PTMC) caused by the enzyme carboxylesterase in vitro. As well as to characterise polymer blends of f-BTI2g-TVTCN and poly(3-hydroxybutyric acid) as core components for organic electrochemical transistors (OETCs). This is to assess the suitability of these polymers in biodegradable biosensors. The degradation study of PTMC showed a lack of degradation in contrast to previous studies performed on the material; previous studies recorded a mass loss of between (5-8)% after two months. The cause for this discrepancy is still unknown but the evidence points to both systematic faults in the gravimetric analysis as well as random errors found in the equipment. The OECT showed that increasing the PHB fraction in the polymer blend resulted in a higher output. The most stable device consisted of a 1:6 blend of f-BTI2g-TVTCN to PHB. Fewer tests were conducted on the 1:10 blend because two devices were damaged during the experiment. The statistical impact of the smaller sample size cannot be overstated so further testing should be conducted to verify the results.

För att skapa ett hållbart samhälle måste material av fossilt ursprung ersättas med förnyelsebara och miljövänliga alternativ. Ett sådant alternativ är cellulosa från vedfibrer, som har stor potential att kunna ersätta många fossila material i framtiden. För att kunna uppnå detta behöver cellulosans egenskaper först modifieras för att passa olika ändamål och helt kunna ersätta fossila alternativ. I detta kandidatexamensprojekt modifierades blekt sulfatmassa, oblekt sulfatmassa, dissolvingmassa och kemitermomekanisk massa (CTMP) genom att introducera kvartära aminer med hjälp av två olika reagens, 2,3-epoxypropyltrimetylammoniumklorid (EPTMAC) och 3-kloro-2-hydroxypropyltrimetylammoniumklorid (CHPTAC). Under projektet undersöktes reagensens reaktionseffektivitet för de olika massorna genom att mäta substitutionsgraden (DS), hur förbehandling i form av torkning och malning påverkar modifieringsreaktionen och den modifierade massans egenskaper, utgångsmassornas svällningsegenskaper, samt mekaniska egenskaper som e-modul, brottstyrka och brottöjning hos pappersark tillverkade av modifierad massa. Resultaten från studien visar att det reaktionseffektivaste reagenset var CHPTAC som gav upphov till en genomgående högre effektivitet än samtliga modifieringar med EPTMAC, men att effektiviteten för respektive reagens är mindre beroende av pappersmassans komposition. Modifiering resulterade i att alla massor fick högre styrka i form av e-modul, brottstyrka och brottöjning. De mekaniska egenskaperna följde inte samma trend som substitutionsgraderna, vilket var oväntat. För att kunna dra mer pålitliga slutsatser skulle ytterligare studier behöva genomföras, inklusive upprepade modifieringar med varierande mängd reagens, mekaniska tester samt analys av ytterligare egenskaper som fibrernas ytor, kristallstruktur och längden på cellulosafibrerna.

In this project, solid sulphur based Li3PS4 electrolytes doped with Li4SiO4 were synthesised using two methods. In method A, a bought β-Li3PS4 electrolyte from Nei Corp was doped with 5 mole per cent Li4SiO4, resulting in a glass-ceramic electrolyte. In method B, the electrolyte was synthesised using 5Li4SiO4-95(75Li2S-25P2S5), resulting in a glassy material. In addition, a reference was synthesised using 75Li2S-25P2S5. Ball milling was the method of choice to dope the glass ceramic electrolyte and synthesise the glassy electrolyte. The dopant Li4SiO4 was synthesised using the chemicals SiO2 and Li2CO3. All samples were analysed using Raman, XPS, XRD, and EIS. In the end, it was found that doping the bought β-Li3PS4electrolyte with Li4SiO4 increased the ionic conductivity. While introducing Li4SiO4 to the glassy electrolyte lowered the ionic conductivity. The increase in ionic conductivity in the glass ceramic electrolyte was partly attributed to the increase in amorphous content, which happened when it was ball-milled and suppressed P-S-P bonds. The decrease in ionic conductivity that happened when doping the glassy material, is most likely caused by residual Li2S that seems unable to react due to the dopant.