This thesis deals with the development and current issues of Li-ion and Li-S accumulators, especially the separators. In the theoretical part is described history of Li-ion batteries, their properties and materials for the positive electrode. Li-S batteries and their problems are also described in this diploma thesis. In the practical part, electrochemical methods were described, and several separator samples with various modifications were created. These samples were then photographed using an SEM electron microscope and evaluated using electrochemical methods.

This thesis deals with a study of lithium-ion batteries. It is focused into negative electrode materials and electrolytes. In this thesis is presented synthesis, electrochemical properties, possibilities to improving negative electrode materials as LTO (Lithium Titanate Oxid) and graphite. These electrode materials were investigated with respect to their compatibility at electrolytes with carbonate solvents, Sulfolane and DMF (DiMethylFormamide) in detail. The main aim of this thesis is to characterize electrode materials and electrolyte properties depending on wide range of temperatures and their comparison for the purpose of achievement of the best solution. The thesis is divided into two main parts. The theoretical part of thesis describes composition, process of synthesis and analysis of lithium-ion cell. Practical part contains measuring and evaluating of charge-discharge and irreversible capacity characteristics related to variety of environmental temperatures.

This diploma thesis deals with the actual problems of sports car. This project solves the basic question of the future ecological cars drive and deals with problems related to ergonomics adherent to this type of car. The work includes a detailed retrieval study of the issue followed by the procedure of designing the car. The conclusion of the thesis deals with the detailed description and an analysis of the concept from several points of view. This thesis is also supplemented by preview of po-sters and multimedia presentation for 3D virtual reality.

This thesis deals with ionic liquids and use of ionic liquids as electrolytes in lithium-ion batteries. Thesis describes basic characteristics of secondary electrochemical cells and characteristics of ionic liquids. Thesis also describes modifications and measurement of ionic liquids. Thesis also presents the results of measurement conductivity and potential window of modified ionic liquids.

LIBs have become an ideal choice in the EVs batteries and stationary storage applications due to their invaluable advantages. The demand for LIBs is projected to increase due to the growth in the sale of EVs. But an average lifespan of LIBs is expected to be around 8 years, thus resulting in the generation of a huge pile of spent batteries after their end of life. The disposal of spent LIBs has several environmental impacts and also results in the loss of valuable metals as a waste. So, efficient, and sustainable recycling methods should also grow at the same pace as of the EVs industries. Li is one of the vital elements for the modern energy revolution and there is a growing demand for its usage in the battery applications. High demand for Li along with supply risks due to its uneven distribution in different geographical locations will increase the Li price. Also, Li was added to the list of EUs critical materials. Currently, only 1% of Li from the end of life products is being recovered. The hydrometallurgy processes based on acid leaching followed by recovery steps are found to be efficient in the recovery of a considerable amount of Li yet there are many drawbacks. Therefore, a combined method such as a thermal treatment followed by water leaching is found to be a promising route to first selectively separate Li from the other valuable metals. The purpose of this research is to investigate the selective leaching of Li from thermally pretreated waste LIBs (by pyrolysis and incineration processes between 400 – 700 ºC for 30, 60, 90min) with water as a leaching agent at high temperature and low L/S ratio. Al salts were also leached along with Li with an efficiency not higher than 3.5%. The finding showed that the time of thermal pretreatment did not have a significant change in Li leaching efficiency. The effect of the S/L ratio showed that the leaching efficiency of Li was higher with an increase in liquid content, keeping the mass of solid constant. At a higher leaching temperature, the leaching efficiency of Li was higher due to an increase in the solubility of Li salts. The highest Li leaching efficiency of nearly 60% was observed from the sample pyrolyzed at 700 ºC for 60 min with the leaching condition S/L ratio = 1:20 g/mL, 80 ºC, 300 rpm, 3 hrs. Furthermore, the tests such as addition of 10% excess carbon during thermal treatment or use of carbonated water during leaching were carried out to enhance the leaching efficiency of Li. However, the test results did not have a significant increase in the leaching efficiency of Li. / LIB har blivit ett idealiskt val i EV-batterier och stationära lagringsapplikationer på grund av deras ovärderliga fördelar. Efterfrågan på LIB bedöms öka på grund av tillväxten i försäljningen av elbilar. Men en genomsnittlig livslängd på LIB förväntas vara cirka 8 år, vilket resulterar i att en enorm hög med förbrukade batterier genereras efter deras livslängd. Bortskaffande av förbrukade LIB har flera miljöpåverkan och resulterar också i förlust av värdefulla metaller som avfall. Så effektiva och hållbara återvinningsmetoder borde också växa i samma takt som inom elbranschen. Li är ett av de viktigaste elementen för den moderna energirevolutionen och det finns en växande efterfrågan på dess användning i batteritillämpningarna. Hög efterfrågan på Li tillsammans med utbudsrisker på grund av dess ojämna fördelning på olika geografiska platser kommer att öka Li-priset. Li läggs också till i listan över EU: s kritiska material. För närvarande återvinns endast 1% av Li från uttjänta produkter. Hydrometallurgiprocesserna baserade på syraläckning följt av återvinningssteg har visat sig vara effektiva vid utvinningen av en betydande mängd Li men det finns många nackdelar. Därför har en kombinerad metod, såsom en termisk behandling följt av vattenlakning, visat sig vara en lovande väg att först selektivt separera Li från de andra värdefulla metallerna. Syftet med denna forskning är att undersöka den selektiva urlakningen av Li från termiskt förbehandlade avfall LIB (genom pyrolys och förbränningsprocesser mellan 400 - 700 ºC under 30, 60, 90 minuter) med vatten som läckmedel vid hög temperatur och låg L / S förhållande. Al-salter lakades också ut tillsammans med Li med en verkningsgrad som inte var högre än 3,5%. Resultatet visade att tiden för termisk förbehandling inte hade någon signifikant förändring av Li-utlakningseffektiviteten. Effekten av S / L-förhållandet visade att urlakningseffektiviteten för Li var högre med en ökning av vätskeinnehållet, vilket höll massan av fast ämne konstant. Vid en högre urlakningstemperatur var urlakningseffektiviteten för Li högre på grund av en ökning av lösligheten av Li-salter. Den högsta Li-lakningseffektiviteten på nästan 60% observerades från provet pyrolyserat vid 700 ° C under 60 minuter med läckningsförhållandet S / L-förhållande = 1:20 g / ml, 80 ° C, 300 rpm, 3 timmar. Vidare utfördes testerna såsom tillsats av 10% överskott av kol under termisk behandling eller användning av kolsyrat vatten under lakning för att förbättra lakningseffektiviteten för Li. Emellertid hade testresultaten ingen signifikant ökning av utlakningseffektiviteten för Li.

The freight transport plays an important role in the development of the economy. However, this comes with an important contribution to greenhouse gas emission. Recently a shift toward heavy-duty electric vehicles has been made, but some issues still need to be tackled. One of them is to develop ways to quickly recharge the vehicle’s batteries without damaging them. In this thesis, we highlight that not only the current but also the battery temperature need to be carefully managed in order to prevent damages during a charging session. To show that, an electrical, thermal and aging model of Li-ion battery is developed. A charging strategy based on a Model Predictive Control algorithm is proposed. The algorithm controls both the battery current and cooling system in order to achieve the optimal balance between the charging speed and the preservation of the battery. The resulting algorithm is tested, in simulation, against a conventional constant current charging in different charging scenarios. The results show an important increase in performance and highlight the role of the battery cooling system in the preservation of the battery. / Godstransporterna spelar en viktig roll för ekonomins utveckling. Detta innebär dock ett betydande bidrag till utsläppen av växthusgaser. På senare tid har en övergång till tunga elfordon skett, men vissa frågor måste fortfarande lösas. En av dem är att utveckla metoder för att snabbt ladda fordonsbatterierna utan att skada dem. I den här avhandlingen lyfter vi fram att inte bara strömmen utan även batteritemperaturen måste hanteras noggrant för att förhindra skador under en laddning. För att visa detta utvecklas en elektrisk, termisk och åldrande modell för Li-ion-batterier. En laddningsstrategi baserad på en algoritm för modellförutsägbar styrning föreslås. Algoritmen styr både batteriströmmen och kylsystemet för att uppnå en optimal balans mellan laddningshastighet och bevarande av batteriet. Den resulterande algoritmen testas i simulering mot en konventionell konstantström laddning i olika laddningsscenarier. Resultaten visar en betydande ökning av prestanda och belyser batterikylsystemets betydelse för bevarandet av batteriet.

Current commercial intercalation cathodes are approaching their theoretical capacity edges, which limits further improvement of the energy density in Li-ion batteries. To overcome this limitation, Li-rich antiperovskite cathodes were developed, utilizing both cationic and anionic redox activities. This class of materials has the general formula (Li2TM)ChO, where TM and Ch represent a transition metal (Fe, Mn, Co) and chalcogen ion (S, Se), respectively. This work focuses on understanding the reaction mechanism, exploring novel approaches for optimizing the electrochemical performance, and developing a scalable synthesis method for the antiperovskite cathodes. Firstly, the effect of substituting S by Se in the solid-state synthesized (Li2Fe)SO on the structural and electrochemical performance is thoroughly investigated. The anionic substitution was found to improve the structural and thermal stabilities of (Li2Fe)SO material. The cyclic voltammetry data confirmed both the cationic (Fe) and anionic (S/Se) redox activities, with possibility of controlling the anionic redox potential through the anionic substitution. It was observed that the electrochemical performance exhibits a non-linear dependence on the degree of anionic substitution. Among the prepared (Li2Fe)S1-xSexO (x = 0.1-0.9) compositions, (Li2Fe)S0.7Se0.3O exhibited the best electrochemical performance with a specific capacity 245 mAhg-1 and good cycling stability at low current rate. Ex-situ and in-situ measurements suggested an enhanced structural stability of (Li2Fe)S0.7Se0.3O during electrochemical cycling compared to (Li2Fe)SO, which could be one of the reasons for its superior performance at low current rates. The second part of this work focuses on understanding the reaction mechanism of (Li2Fe)SeO prepared by solid-state reaction (SSR) method and exploring the impact of cationic substitution of Fe by Mn on its structural and electrochemical properties. Electrochemical investigations showed that the cationic redox activity leads to a reversible cycling behaviour, indicating its role in the stable performance. Whereas, the anionic redox activity leads to partial decomposition of the (Li2Fe)SeO cathode to an electrochemically active phase. In general, although the electrochemical activity of the phase resulting from the partial decomposition of any antiperovskite composition can compensate the initial capacity loss, it opens a channel for capacity fading over long term of cycling. The (Li2Fe)SeO cathode could deliver an initial specific discharge capacity of 165 mAhg-1, which declined to only 140 mAhg-1 after 100 cycles, indicating a good cycling performance. Even at high current rate (1C), the (Li2Fe)SeO could provide a reasonable specific capacity of 100 mAhg-1. Replacing Fe with Mn reduced the overall redox activity of the cationic and anionic redox processes, when using active material: carbon: binder weight ratio of 70:15:15 wt. %. This may result from impeded kinetics and the Jahn-Teller effect associated with Mn2+/3+ redox. However, low substitution levels can be beneficial in optimizing the performance while minimizing the negative effects associated with Mn2+/3+ redox pair. Modifying the electrode ratio to 85:10:5 wt. % improved the specific capacity for (Li2Fe0.9Mn0.1)SeO, surpassing that of the unsubstituted (Li2Fe)SeO cathode. These findings highlight the role of controlled substitution and electrode ratio in optimizing the electrochemical performance of antiperovskite cathodes. The third part of this work focuses on developing scalable, controllable, and sustainable synthesis of antiperovskite cathodes using mechanochemical (MC) method based on ball milling (BM), which is crucial for practical application. Both (Li2Fe)SeO and (Li2Fe)SO antiperovskite cathodes have been successfully prepared by direct MC without the need for external heating, which is advantageous for energy saving. Post-heat treatment after the milling was found to be an effective strategy for controlling the morphological and electrochemical properties of both materials. Both ball-milled materials revealed similar reaction mechanism to the (Li2Fe)SeO prepared by SSR method, involving both cationic and anionic redox activities. The ball-milled (Li2Fe)SeO displayed an average specific discharge capacity of 255 mAhg-1 at 0.1C and 138 mAhg-1 at 1C in the potential range 1-3 V. Transmission electron microscopy and magnetic investigations revealed a partial conversion of the mechanochemically synthesized (Li2Fe)SeO into an electrochemically active Fe1-xSex phase during the anionic redox process. On the other hand, mechanochemically synthesized (Li2Fe)SO exhibited an average specific discharge capacity of 340 and 133 mAhg-1 at 0.1C and 1C, respectively, in the potential range 1-3 V. Excluding the anionic redox activity of both materials by restricting the potential scanning range was found to be advantageous for enhancing the cycling stability over long range of cycling. This highlights the critical role of controlling the potential range on the electrochemical performance and cyclability of these materials.

This thesis investigates several approaches to the development of high-performance batteries. A general background to the field and an introduction to the experimental methods used are given in Chapters 1 and 2 respectively. Chapter 3 presents a study of ordered and disordered LiNi₀.₅Mn₁.₅O₄ materials produced using an optimised resorcinol-formaldehyde gel (R-F gel) synthetic technique. Both materials exhibited good electrochemical properties and minimal side reaction with the electrolyte. Structural analyses of the materials in various states of discharge and charge were undertaken, and from these the charge / discharge processes were elucidated. In chapter 4 R-F gel synthesised Li(Ni₁/₃Mn₁/₃Co₁/₃)O₂ is studied and found to exhibit a high degree of structural stability on cycling, as well as excellent capacity, cyclability and rate capability. Photoelectron spectroscopy studies revealed that the R-F gel derived particles have highly stable surfaces. A discussion of the results and their significance, with particular regard to the outstanding electrochemical performance observed, is also presented. Chapter 5 sets out an investigation into the nature of R-F gel synthesised 0.5Li₂MnO₃:0.5LiNi₁/₃Mn₁/₃Co₁/₃O₂. The electrochemical data revealed that, after an initial activation stage, the R-F gel derived material exhibited a high capacity, good cyclability and exceptional rate capability. This chapter also considers some initial structural investigations and the electrochemical processes occurring on charge. In chapter 6 the use of ether-based electrolytes, combined with various cathode materials, in lithium-oxygen batteries is examined. The formation of decomposition products was observed, and a scheme suggesting probable reaction pathways is given. It was noted that significant quantities of the desired discharge product, lithium peroxide, were formed on the 1st cycle discharge, implying some electrolyte / cathode combinations do demonstrate a degree of stability. A summary of the results and a discussion of their significance are also included.

Batteries have imparted momentum to the process of transition towards a green future. However, mass application of batteries is obstructed due to their explosive nature, a trait specific to Li-Ion batteries. To cater to an efficient battery utilization, an introduction of a battery management system would provide an ultimate solution. This thesis deals with different aspects crucial in designing a battery management system for high energy as well as high power applications. To build a battery management system capable of predicting battery behavior, it is necessary to analyze the dynamic processes happening inside the battery. Hence, a battery equivalent circuit model is proposed in this thesis as well as proper analysis is done in MATLAB to project a generic structure applicable to all Li-Ion chemistries. The model accounts for all dynamic characteristics of a battery including non-linear open circuit voltage, discharge current and capacity. Effect of temperature is also modeled using a cooling system. The model is validated with test current profiles. Less than 0.1% error between measured and simulated voltage profiles indicates the effectiveness of the proposed model to predict the runtime behavior of the battery. Furthermore, the model is implemented with the energy as well as the power battery pack. State of charge calculations are performed using the proposed model and the coulomb counting method and the results indicate only a 4% variance. Therefore, the proposed model can be applied to develop a real-time battery management system for accurate battery states estimation.

Conducting polymer hydrogels (CPHs) is a class of unique materials that synergize the advantages of conducting polymers (CPs) and polymer hydrogels together. It has been employed in many high-performance electrochemical devices for years, such as energy storage and biosensors. However, large limitations of applying CPHs into the abovementioned areas have been facing the researcher for a long time, mainly due to the difficulties from complicated materials synthesis and untenable nanostructures for potential applications. The drawbacks of previously reported CPHs have put numerous disadvantages onto their applications, partially because they have, for example, high prices, untunable microscale or nanoscale architectures, environmentally hazardous properties, and unscalable and time-consuming synthesis processes. In this thesis, we proposed a novel route for carrying out CPHs by one-step organics synthesis at ambient conditions. The CPHs have hierarchically porous nanostructures crosslinked in a three-dimensional (3D) way, which enable its stable mechanical, unique chemical and physical properties, and outstanding electrochemical properties for potential applicability in long-term energy storage devices and highly sensitive biosensors. With highly controllable nanostructures of the CPHs, our novel concept and material system could possibly be utilized in a broad range of electrochemical applications, including but not limited to lithium-ion batteries (LIBs) electrodes, electrochemical capacitors (ECs), biofuel cells, medical electrodes, printable electronic devices, and biosensors. / text