Integrated Energy Conversion and Storage Device for Stable Fast Charging Power Systems

Charging up Stationary Energy Storage

Energy devices are having an increasing technological impact on our society and have become an essential part of our daily lives. Printing technology has been used to manufacture a wide range of energy storage and conversion devices, including solar cells, supercapacitors, lithium-ion batteries, zinc-ion batteries, nanogenerators, etc. High-resolution screen-printing technology is widely used in the fabrication of commercial solar cells. The development of flexible energy devices is a key part of the realization of wearable electronics, and printing technology has unique advantages. In this chapter, the structure and mechanisms of conventional printed energy storage and conversion devices and manufacturing strategy are illustrated.

Introduction Electrochemical energy conversion and storage are of large importance in future energy technology [1]. The increasing market share of renewable energy sources requires corresponding storage options in order to match electricity supply and demand. In this regard, electrochemical storage or (photo)electrochemical conversion of electricity to hydrogen or methane gas may provide solutions [2]. Even more significant is the role of electrochemistry in electromobility. The electrification of cars is required considering the increasing number of electric vehicles worldwide, especially in Asia, and the associated environmental problems and resources consumption [3]. Li-ion battery powered cars as well as fuel cell vehicles both will play an important role. Aside from these aspects, electrochemistry is of importance in the preparation of (nano-) materials for energy conversion devices. In some of these fields, ionic liquids can offer significant enhancements compared to conventional electrolytes. Therefore the application of ionic liquids in energy conversion and storage is reviewed, before focusing on the more specific topic of batteries for electromobility. Li and Mg Ion Batteries Rechargeable lithium-ion batteries have been advanced and success-fully commercialized in the past two decades, particularly in the areas of portable and mobile applications. Nowadays, the advancement of hybrid electrical vehicles (HEVs) and electrical vehicles (EVs) technologies depends strongly on the availability of Li-ion battery systems improved with respect to cyclability and energy density [4]. There is an increasing demand of batteries for transportation. This raises big challenges for the next generation rechargeable batteries concerning cost, safety, power and energy density, cycle life, etc [5]. Those batteries in most cases have a highly flammable organic electrolyte, or in some cases a solid electrolyte suffering from limited conductivity. Here ionic liquids offer an alternative combining a significantly improved safety level with the advantages of a liquid electrolyte. In order to optimize the electrode materials and the electrolyte composition an understanding of the physico-chemical processes in the battery at the nanoscale is required. Therefore, various scanning probe microscopy (SPM) studies have been devoted to investigate the nanoscale electrochemical reactions and the physical basis of imaging mechanisms [6]. In our work, we study the processes of ion insertion and SEI formation on model anodes and cathodes using Electrochemical Scanning Tunneling Microscopy (EC-STM). These measurements are performed both in classic organic electrolytes, i.e. mixtures of ethylene carbonate / dimethyl carbonate and LiPF6, as well as in ionic liquids. Figure 1 gives an example for the initial stages of SEI formation in a classical organic electrolyte. Studies are also performed for Mg ion batteries that still suffer from a number of problems [7]: For this system it has been shown that using ionic liquids in combination with Grignard reagents, reversible Mg electroplating is possible, thus permitting the use of Mg anodes [8]. Therefore Mg insertion in HOPG and cathode materials, mainly V2O5, are studied as well in such electrolytes. Acknowledgments Funding by BMBF under Project Number 16N11930 and by the Fuel Cell and Hydrogen Initiative Joint Undertaking under contract number 303492 (CathCat) are gratefully acknowledged.

One of the greatest challenges for the modern world is the ever-increasing demand of energy, which may soon outstrip the amount of natural resources that can be obtained using currently known energy conversion and energy storage technologies such as solar cells, fuel cells, lithium ion batteries, and supercapacitors. It appears that the maximum output efficiencies of these devices have already reached the intrinsic limits of almost all electrocatalyst materials. Hence, it is a high time to think about new material architectures by controlling size, shape, and geometry, as well as composition that can potentially make a significant improvement in the performance of these electrochemical devices. Among several known electrocatalyst materials are nanomaterials and their composites due to their unique electrical, mechanical, physical, chemical, and structural characteristics. These materials have opened a whole new territory of possibilities in designing high performance energy storage and conversion devices. In this chapter, the authors review the recent progress in energy storage and conversion devices that utilize various nanomaterials and their composite materials and identify future directions in which the field is likely to develop.

Over the last few decades, there has been increasing interest in the design and construction of integrated energy conversion and storage systems (IECSSs) that can simultaneously capture and store various forms of energies from nature. A large number of IECSSs have been developed with different combination of energy conversion technologies such as solar cells, mechanical generators and thermoelectric generators and energy storage devices such as rechargeable batteries and supercapacitors. This review summarizes the recent advancements to date of IECSSs based on different energy sources including solar, mechanical, thermal as well as multiple types of energies, with a special focus on the system configuration and working mechanism. With the rapid development of new energy conversion and storage technologies, innovative high performance IECSSs are of high expectation to be realised for diverse practical applications in the near future.

To improve the safety of Li ion battery (LIB) in high energy applications, numerous efforts have been made in terms of choosing materials to be used.[1-2] However, these attempts have been limited by thermal stability and durability of separator including electrolyte. In this study, anodic aluminum oxide (AAO) film was used as a separator in Li ion battery for superior performance over commercialized polyolefin-based separator.The AAO film has been prepared by two-step anodization method which is consisted of etching and anodizing processes. The as-prepared AAO film is around the 20 um thick and they showed perpendicular nanopore arrays having a diameter of 40nm.The porosity of the AAO film is calculated about 58.79 %. [3] That value is higher than that of the commercial separator (55%, celgard 2500) The wettability of the AAO film was analyzed using contact angle measurement with liquid electrolyte (1M of LiPF6 in EC:DMC:DEC=1:1:1 (v/v/v)). The AAO film shows higher wettability with smaller contact angle as value of 0o than commercial separator (36o). Small contact angle means low cell resistance which is suitable for high power LIBs. [3]The test for electrolyte absorbance property of the AAO film was conducted. The electrolyte uptakes of the AAO film and the commercial separator are determined to be 126.88 wt% and 264.28 wt% respectively. [3] The density of the AAO film (3.98g/cm3) is smaller than the commercial separator (14.23g/cm3), so they required less electrolyte to operate LIB. Although less amount of electrolyte is used, the AAO film shows higher ionic conductivity of 2.06 mS/cm with SUS electrode than the commercial separator (0.66 mS/cm). This can be explained by low contact angle, which is agreed with low bulk resistance and higher permittivity of AAO film, it contributes to ionic conductivity. (Dielectric constant of AAO film : 28.59, relative permittivity of commercial separator: 9.06 at 1KHz)The interfacial compatibility of lithium metal with separator was investigated by AC impedance with a lithium metal anode. It could be observed that the interfacial resistance was 118.33 Ω for the AAO and 141.92 Ω for the commercial separator, respectively. It means that the AAO film provide better interfacial characteristics for LIB.Capacity of the AAO explored with half-cell performance, while LiFePO4was applied as cathode from 2V to 4.2V. The AAO film and commercial separator showed similar capacity at 0.2C, the highest values were 123.0 mAh/g for AAO film and 122.6 mAh/g for commercial separator. Capacity recovery test was evaluated to confirm the correspondence with high energy LIB. Commercial separator was degraded from 1C rate and did not recovered. However, in case of AAO film, the capacity maintained 110.9 mAh/g at 0.5C, 88.4 mAh/g at 1C rate and recovered 121.1 mAh/g after investigation. And the AAO film showed high columbic efficiency over 98% at 0.5C rate. These excellent electrochemical characteristics related to Li dendrite. The AAO film can mechanically suppress the formation of Li dendrites, and homogeneous current distribution derived from well-ordered nanopores of the AAO film helps prevent Li dendrite growth.In conclusion, the AAO film is a promising separator for LIB, especially in high energy performance, and durability test is needed for further study in the near future.ReferenceBruce, P. G.; Scrosati, B.; Tarascon, J. M., Angew. Chem. Int. ed., 47, 2930 (2008).D. Bansal, B. Meyer, M. Salomon, J. Power Sources 178(2), 848 (2008).J. Fang, A. Kelarakis, Y.-W. Lin, C.-Y. Kang, M.-H. Yang, C.-L. Cheng, Y. Wang, E.P. Giannelis, L.-D. Tsai, Phys. Chem. Chem. Phys. 13, 14457 (2011).

Boosted by the increasing demand for clean and portable energy resources, there have been tremendous efforts being made in the energy harvesting and energy storage materials and devices, such as solar cells, fuel cells, Li-ion batteries etc. Since its first commercial debut in 1991, Li-ion battery has achieved significant progress in energy storage performances. The development of nanostructured electrode material is regarded as one of the key potentials for the further advancement in Li-ion batteries. This paper highlights our recent studies in the synthesis and characterization of nanostructured electrode materials for high-performance Li-ion batteries. The main focuses are on the binder-less and additive-free vanadium oxide films and lithium iron phosphate - carbon nanocomposite films via sol-gel processing. Enhanced Li <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> intercalation capacities, improved rate capabilities and better cyclic stability were achieved by architecting micro- or nanostructure, controlling materials crystallinity and introducing desired defects on surface and/or in bulk.

Current challenges and future prospects for a highly efficient (>20%) kesterite CZTS solar cell: A review

Integrated energy conversion and storage devices: Interfacing solar cells, batteries and supercapacitors

Advanced nano-structured materials have emerged as key elements in enhancing the acting of strength storage devices in the way that fuel cells, solar cells, Li-ion batteries, super-capacitors, and capacitors. These matters offer superior characteristics including high surface area, enhanced electrical conductivity, and improved mechanical strength, enabling efficient energy storage and conversion processes. In fuel cells and solar cells, nano-structured materials like graphene, quantum dots, and alloy oxides facilitate rapid charge transfer and increase design efficiency. In Li-ion batteries, nano-structured electrodes reinforce ion diffusion and provide higher energy densities. Super-capacitors benefit from nano-structured carbon materials with increased capacitance and faster charge/discharge rates. Capacitors with nano-structured dielectrics exhibit enhanced energy storage capabilities and prolonged lifespan.

With the rapid development of the new energy sector and lithium-ion (Li-ion) battery technologies, using Li-ion batteries with high energy density and high discharge rate to form the primary energy subsystem can further improve the compactness and miniaturization level of pulsed power systems. In traditional electric power systems, Li-ion batteries normally operate under the discharge condition of low current and long time. However, as the main power source of pulsed power systems, it is required that Li-ion batteries should have the capability for high-rate pulse discharge. To ensure the safe and reliable operation of the battery energy storage system, it is necessary to conduct the parameter identification of the Li-ion battery model to establish an accurate pulse discharge model under such working conditions. This paper focuses on the discharge characteristics of a cylindrical high-rate single Li-ion battery with a capacity of 3 Ah. At a 20 C rate, the discharge data were obtained when the pulse repetition frequency was 10 Hz and the duty cycle was 90%. By using the mathematical expressions of the Thevenin equivalent circuit model, the recursive relationship of the circuit parameters was obtained, and the parameter identification of the battery model was conducted based on the experimental data by using the genetic algorithm. The results show that the fitting accuracy of the parameter identification reaches 0.9995, indicating the high precision of the model for the Li-ion battery. This work provides a significant reference for the modeling and parameter identification of Li-ion batteries under high-rate pulse discharge conditions.

The continuous consumption of non-renewable sources of energy causes several environmental problems such as greenhouse effect, global warming, pollution, etc. For development of clean and sustainable environment, our society urges an alternative of non-renewable source of energy such as fuel cell, solar cell, electrochemical capacitors, splitting cells, photochemical cell, etc. It is well known that metal sulphides (MS), where M = Ni, Co, Cu, Ti, W, Sn, etc. are the analogous of metal oxides and they emerged as new materials for energy conversion and storage devices due to their high redox activity, longer cyclic stability, high power density, and high energy density. From these metal sulphides, Nickel sulphide (NiS) attracts much more attention due to its high electrochemical activity, low cost, binary phases, superior physical and chemical properties and eco-friendly, etc. Nickel sulphide nanostructures have high surface to volume ratio, thermal stability, controlled morphology, etc. In this chapter, we discuss the various parameters which affect the physical and chemical properties of nickel sulphide such as capping agent, temperature, molar concentration of nickel and sulphur source, solvents, synthesis method, etc. Also this chapter discusses the binary phases of nickel sulphide, and their importance in energy conversion and storage devices. Each phase of nickel sulphide has its own applications such as NiS2 is used as counter electrode, β-NiS as supercapacitors, Ni3S2 as electrode in Lithium ion batteries, etc.KeywordsNano/MicrostructuresNickel sulphideSolar cellSupercapacitor

Chapter 18 - Hexagonal boron nitride for energy storage and conversion

Application of nanocellulose in solar photo/thermal energy conversion and electrochemical energy storage devices

Increasing the global energy demand as well as the carbon dioxide (CO2) level in the atmosphere caused by burning fossil fuel as the main source of energy motivate the development of green energy technologies. However, the real activity improvement for these technologies is mainly impeded by intermittent nature of renewable energy technologies. One smart approach to overcome this issue is to store energy into the chemical bonds1–6 using inexpensive and efficient energy conversion and storage technologies. In these systems, energy can be converted or stored into chemical bonds as a form of fuels or electricity using renewable energy sources, e.g., solar and wind energy7–9. Despite recent progress, the development of these systems is advanced far more slowly due to the expensive and less efficient materials employed in these technologies. Here, I will present my aim to design, synthesis, and characterization of inexpensive earth-abundant transition metal dichalcogenide class of materials suitable for energy conversion and storage systems. I have tested the performance of this class of catalysts for the carbon dioxide (CO2) reduction reaction, oxygen reduction, oxygen evolution reactions. The results indicate (i) 100 times higher turn over frequency- per atom activity- far exceeding the performance of state-of-the-art catalysts for CO2 reduction reaction, and (ii) a highly efficient bi-functional catalyst for oxygen reduction and evolution reactions in the aprotic media compared to conventional noble metal catalysts used for the same application (e.g., Platinum and Gold). I also tested the performance of molybdenum disulfide nanoflakes (MoS2 NFs) -a versatile member of TMDCs- in lithium-air batteries known as a promising alternative to the conventional lithium-ion batteries. The results indicate that MoS2 NFs in the ionic liquid EMIM-BF4 electrolyte performs remarkably well in the actual air environment with a small discharge/charge potential gap as well as good stability and cyclability up to 550 cycles without any evidence of failure. I will discuss these and other results including the potential of our recent discovery to open a new route towards energy efficient, highly active and cost-effective energy storage and conversion systems to replace fossil fuels.