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This paper presents experimental investigations into a hybrid energy storage system comprising directly parallel connected lead-acid and lithium batteries. This is achieved by the charge and discharge cycling of five hybrid battery configurations at rates of 0.2–1C, with a 10–50% depth of discharge (DoD) at 24 V and one at 48 V. The resulting data include the overall round-trip efficiency, transient currents, energy transfers between the strings, and the amount of energy discharged by each string across all systems. The general observation is that the round-trip efficiency drops from a maximum of around 94–95% in the first stages of the charge/discharge process, when only the Li-ion strings are active, to around 82–90% when the lead-acid strings reach a DoD of up to 50%. The most important parameters in the round-trip efficiency function are the ratio between the Li-ion and lead-acid energy available and the charge/discharge current. The energy transfer between the strings, caused by the transient currents, is negligible in the first stages of the discharge and then grows, with the DoD peaking at around 60% DoD. Finally, during the first stage of discharge, when only the Li-ion strings are active, the amount of energy discharged varies with the discharge C rate, decreasing to almost half at between 0.2 and 1C. [ABSTRACT FROM AUTHOR]

Lithium iron phosphate (LFP) has become a focal point of extensive research and observation, particularly as a cathode for lithium-ion batteries. It has extensive uses in electric vehicles, stationary power storage systems, and portable electronic devices. To further enhance the performance, one crucial area of focus is optimizing the cathode materials. This optimization involves improving key parameters such as conductivity, rate capability, and energy density. In this context, researchers have explored various cathode materials in combination with different conducting polymers, including poly(aniline), poly(thiophene), poly(pyrrole), poly(acetylene), and more. These conducting polymers are integrated into the cathode to boost the overall electrochemical behavior of LFP batteries. The objective is to assess how these electrochemical properties of conducting polymers influence the overall performance of LFP batteries. This research aims to provide a complete evaluation of conducting polymer-based cathode materials and to establish a solid foundation for selecting suitable polymers that support effectively as a cathode material. Such investigations are pivotal for advancing the development of these batteries with improved capabilities, ultimately leading to more efficient and reliable energy storage solutions intended for a varied choice of applications. [ABSTRACT FROM AUTHOR]

The vast majority of Earth-orbiting satellites carry an electrical power subsystem (EPS) which main components are solar panels and secondary batteries. During eclipse periods, satellites are powered only by rechargeable batteries which have a large energy density but a limited power density. This fact limits the power capabilities of small satellites during eclipse periods. Due to the large power density of Supercapacitors (SCs), ground and on-orbit tests have been conducted to verify their applicability on satellite EPSs. At the moment, no studies are underway on the issue of sizing SCs for eclipse operations. Hybrid configuration could reduce the mass and volume of EPS or maintain those reference values but increasing peak power capabilities. This paper deals with this issue. On the one hand, novel analytical expressions of a variable capacitance SCs are derived, including time–voltage dependence in constant power applications. Also an equivalent formulation for a SCs bank (SCsB) is derived. On the other hand, a SCsB sizing procedure is presented, considering the energy and power requirements of a particular space mission as an input. Finally, a simple mission is analysed, the results showing an improvement on the hybrid EPS design with respect to the traditional, being the mass reduction of 36%. • Implementation of a simple but accurate supercapacitor (SC) model for spacecraft applications. • Innovative analytical expressions of the performance of a SC in constant power applications. • Novel determination of the electrical parameters of a SCs bank, treated as an equivalent SC model. • Estimation of key variables in the operation of hybrid storage systems for space applications. • Preliminary design of a SCs bank devoted to supply high power during eclipse times. [ABSTRACT FROM AUTHOR]

To meet the load voltage and power requirements for various specific needs, a typical lithium–ion battery (LIB) pack consists of different parallel and series combinations of individual cells in modules, which can go as high as tens of series and parallel connections in each module, reaching hundreds and even thousands of cells at high voltage (HV) levels. The inhomogeneity among the cells and modules results in voltage imbalances during operation and reduces the overall system efficiency. In this work, a robust and flexible active balancing topology is presented. It can not only mitigate the charge imbalance within a module, i.e., intramodular equalization, but also help to balance the state of charge (SoC) level of the modules in a high voltage pack, i.e., intermodular equalization, which is an often-overlooked topic. The proposed concept was proven by experimental verification on parallel and series configurations of cells in realistically sized modules and practical battery management system (BMS) hardware, when the LIB was both idle and under load. [ABSTRACT FROM AUTHOR]

Energy storage technologies can act as flexibility sources for supporting the energy transition, enabling the decarbonisation of the grid service provision and the active engagement of the customers (both prosumers and consumers), opening for them new business opportunities. Within storage technologies, Lithium-ion (Li-ion) batteries represent an interesting solution for dealing with the majority of these services. In this context, this study addresses an evaluation of economic, environmental and geopolitical risks with reference to the critical raw materials used in the manufacturing of Lithium Iron Phosphate (LFP) Li-ion batteries. The assessment entailes grid and prosumer services that these batteries can provide. The exploited economic indicator is the Levelised Cost of Storage, whereas six environmental indicators are used for environmental impact estimation. Cycle stages accounted for in the analysis are the manufacturing and use phases. Finally, the evaluation of the impact of critical raw materials is performed by deploying a Supply Risk indicator, which is instead assessed considering every single material and the overall risk for the battery. High-risk materials are represented by Graphite and Phosphorous. Results denote that, for each service, the number of cycles and the discharge duration are pivotal to make the investment economically and environmentally sustainable. The reduction in the Net Import Reliance, as well as the increase in the Recycling Rate, could sensibly reduce the risk associated with battery raw materials. [ABSTRACT FROM AUTHOR]

Summary: The great interest to develop the elevated capacity of silicon (Si)‐based anode material is the future necessitate for Li‐ion batteries. The three‐dimensional (3D) microsphere Si@MX‐RG nanocomposite was synthesized employing the facile spray drying method. Moreover, silicon (Si) with sponge‐like few‐layer 2D materials (MXene/reduced graphene [MX‐RG])‐based nanostructure composite has been prepared using a spray dryer. As‐prepared MX and graphene are correspondingly derived from (LiF‐HCl) chemical etching and chemical oxidation, respectively. The FE‐SEM surface morphological views explored highly crumbled pure MX, Si@MX, Si@MX‐RG spray‐dried microsphere particle size ranges from 500 nm to 1 μm. The observed morphology results explored novel crumbled 3D nature morphology. The electrochemical performances of pure MX, Si@MX, Si@MX‐RG microsphere measured employing cyclic voltammetry (CV) revealed good anodic and cathodic peaks at 0.01–1.5 V, and electrochemical impedance spectroscopy (EIS) was analyzed for charge transfer resistance (Rct) of 42 Ω. The galvanostatic charge‐discharge (GCD) profile for Si@MX‐RG microsphere explored 2723 mAh/g anode capacity for the initial cycle, and its initial columbic efficiency (ICE) is 89.1% and it is greatly improved with the second cycle (96.8%). A high reversible 1422 mAh/g specific capacity at 3 C is revealed at 200 cycles. The excellent cycle stability and better rate capability explored exclusive structural devices of novel microspheres. Hence, we confirmed the MX and RG sheets wrapped by silicon cores are having superior conductive MX‐RG and efficiently improve electrical conductivity. [ABSTRACT FROM AUTHOR]

Nanoscale morphology has a direct impact on the performance of materials for electrochemical energy storage. Despite this importance, little is known about the evolution of primary particle morphology nor its effect on chemical pathways during synthesis. In this study, operando characterization is combined with atomic‐scale and continuum simulations to clarify the relationship between morphology of cathode primary particles and their lithiation during calcination of LiNi0.8Mn0.1Co0.1O2 (NMC‐811). This combined approach reveals a key role for surface oxygen adsorption in facilitating the lithiation reaction by promoting metal diffusion and oxidation, and simultaneously providing surface sites for lithium insertion. Furthermore, oxygen surface termination is shown to increase the activation energy for sintering, leading to smaller primary particle sizes at intermediate temperatures. Smaller particles provide both shorter diffusion lengths for lithium incorporation and increased surface site density for lithium insertion. These insights provide a foundation for more tailored syntheses of cathode materials with optimized performance characteristics. [ABSTRACT FROM AUTHOR]

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In this paper, we explore how effectively renewable generation can be used to meet a country's electricity demands. We consider a range of different generation mixes and capacities, as well as the use of energy storage. First, we introduce a new open-source model that uses hourly wind speed and solar irradiance data to estimate the output of a renewable electricity generator at a specific location. Then, we construct a case study of the Great Britain (GB) electricity system as an example using historic hourly demand and weather data. Three specific sources of renewable generation are considered: offshore wind, onshore wind, and solar PV. Li-ion batteries are considered as the form of electricity storage. We demonstrate that the ability of a renewables-based electricity system to meet expected demand profiles can be increased by optimising the ratio of onshore wind, offshore wind and solar PV. Additionally, we show how including Li-ion battery storage can reduce overall generation needs, therefore lowering system costs. For the GB system, we explore how the residual load that would need to be met with other forms of flexibility, such as dispatchable generation sources or demand-side response, varies for different ratios of renewable generation and storage. [ABSTRACT FROM AUTHOR]

Motivation and complex process of energy storage technology and converter topology design suitable for integration in thermal power plant systems to improve flexibility and primary frequency control is presented in the paper. The case study of typical thermal power plant is included and optimal power and capacity are determined. Next, there are discussed and compared perspective accumulation technologies. Most perspective state of the art battery-based technologies are further in detail evaluated including employed methodology. The next part is focused on suitable converter topology design. Employed converter control algorithms including simulation results are presented. [ABSTRACT FROM AUTHOR]

• Recent information has been compiled on the application of MOFs for Li-Batteries applications. • MOFs and their composites have been discussed as a cathode/anode material for various Li-batteries. • Performance of MOF-composites is reviewed in terms of specific capacity and cyclic stability. • MOF and their composites are discussed in detail for Li-HEC in separate section. Metal organic frameworks (MOFs) have emerged as a novel class of advanced functional materials due to their many well-known merits (e.g., ultrahigh porosity, favorable pore size distribution, easy functionalization, and structural tailorability). However, their use in various electronics applications is restricted due to their insulating nature. Therefore, a need arises to intercalate MOFs with various functional/conductive materials for synergistic applications like electrode materials (e.g., diverse Li-ion batteries: LIBs). In this review, the recent developments on pristine MOFs and their derived nanostructures (e.g., nanoporous carbons and metal oxides) for electrode applications are discussed in detail. We focused on the recent applications of various MOF-based composites in anodic/cathodic materials (e.g., LIBs, lithium-sulfur batteries (Li-S), lithium-air batteries (Li-O 2), and lithium hybrid electrochemical capacitors (Li-HEC)) along with details associated with their electrochemical performance. This review is expected to help materials scientists to construct a roadmap for the selection of the best possible electrode materials for LIBs. [ABSTRACT FROM AUTHOR]

With demand for the natural resources exceeds a certain threshold, it leads to a global ecological threat like the "Amphhan" catastrophe that had ravaged the eastern part of West Bengal during the month of February 2020 that resulted in the loss of lives and economic activity which is yet to be regained with its earlier momentum. The inflicted calamity has given a "blow" as well as "boost" to renewable energy sector that leads to greater seriousness on development of the energy storages devices/stations in the country. While India has already achieved 374 GW of total installed capacity of power generation in which the contribution from the thermal sector is about 62 per cent and that of the RP is about 22 per cent that comes to 90 GW as of today and 60 GW is under pipeline or under construction or under tendering process. The year 2020 is undoubtedly a year of change and the COVID-19 pandemic situation together with enforced lockdown in several parts of the country and even in globe has forced people to think differently to remain relevant against the New-Normal. In order to choose the sources of energy that does not cause pollution to the surrounding environment, the RET is the best and most favourable options to opt for along with the battery storage devices for making the power available throughout the day-long and even when the sun sets. Most of the batteries currently produced and used in our country is lithium-ion based and is mostly imported. To be on the self-reliant mode and moving towards "Atmanirbhar Bharat" through "Make in India" we need to have more and more indigenous manufacturer of Li-ion batteries. Good news is that 10 Indian companies have already procured manufacturing technology from DRDO and large scale production of indigenous Li-ion batteries is expected soon. The National Energy Mission of the Government of India has just rolled out with a focus on the Make in India and is envisioned to take all necessary formalities and policy decisions to be adopted to incentivise advanced energy storage manufacturing in India through the application of innovation and new technology options that are available. As a science communicator, the authors strongly opine that with the appropriate support from the Government of India through the policy decisions by the Niti Aayog, India will be one of the top markets for the energy storage adoptions and manufacturing and is another way forward to mitigate the climate change by producing electricity free from carbon dioxide emissions into atmosphere and provide green energy for sustainable path of development. As we see that the energy storage is a new thrust area along with introduction of FGD technology retrofitting with the thermal power plant, we look forward to the new ecosystem to be achieved by 2030. [ABSTRACT FROM AUTHOR]

Abstract Road transportation is heading towards electrification using Li-ion batteries to power electric vehicles offering eight or ten years' warrant. After that, batteries are considered inappropriate for traction services but they still have 80% of its original capacity. On the other hand, energy storage devices will have an important role in the electricity market. Being Li-ion batteries still too expensive to provide such services with economic profit, the idea to reuse affordable electric vehicle batteries for a 2nd life originated the Sunbatt project, connecting the automotive and electricity sectors. The battery reuse is, by itself, a path towards sustainability, but the cleanliness of energy storage also depends on the electricity generation power sources and the battery ageing or lifespan. This paper analyses the rest of useful life of 2nd life batteries on four different stationary applications, which are: Support to fast electric vehicle charges, self-consumption, area regulation and transmission deferral. To do so, it takes advantage of an equivalent electric battery-ageing model that simulates the battery capacity fade through its use. This model runs on Matlab and includes several ageing mechanisms, such as calendar ageing, C-rate, Depth-of-Discharge, temperature and voltage. Results show that 2nd life battery lifespan clearly depends on its use, going from about 30 years in fast electric vehicle charge support applications to around 6 years in area regulation grid services. Additionally, this study analyses the day-to-day emissions from electricity generation in Spain, and states that grid oriented energy storage applications will hardly offer environmental benefits in the nearby future. On the other hand, applications that go by the hand of renewable power sources, such as self-consumption applications, are much more appropriate. Graphical abstract Image 1 Highlights • Lifespan estimation of 2nd life EV batteries on stationary Applications. • Lifespan goes from 30 to 6 years depending on the application. • Battery reuse enhances circular economy. • Grid oriented applications with batteries do not offer environmental benefits. • Batteries should go by the hand of renewable energy power sources. [ABSTRACT FROM AUTHOR]

In this paper, a hybrid storage system solution consisting of flywheels and batteries with a Lithium-manganese oxide cathode and a graphite anode is proposed, for supporting the electrical network primary frequency regulation. The aim of the paper is to investigate the benefits of flywheels in mitigation of the accelerating aging that li-ion batteries suffer during the grid frequency regulation operation. For this purpose, experimental aging tests have been performed on a lithium-manganese oxide battery module and an electrical battery model which takes into account the battery aging has been developed in a Simulink environment. Then, a flywheel electrical model has been implemented, taking into account the thermal and the electromechanical phenomena governing the electrical power exchange. This more complete model of a hybrid storage system enables us to simulate the same aging cycles of the battery-based storage system and to compare the performances of the latter with the hybrid storage system. The simulation results suggest that suitable control of the power shared between the batteries and the flywheels could effectively help in countering Li-ion battery accelerated aging due to the grid frequency regulation service. [ABSTRACT FROM AUTHOR]

Dehydration of the alkali ions upon charging determines the capacity of the supercapacitor. [Display omitted] • Novel Na- and K-based electrolytes were compared to traditional Li-ion electrolytes. • The sodium-based aqueous electrolyte exhibits the lowest capacitance. • The desolvation of an alkali ion is en assential state of supercapacitor charging. Electrochemical energy sources support the growth in performance and portability of consumer electronics. Further sustainable development assumes an atomistically precise understanding of how the electrolyte binds to the electrode in the charged and uncharged states of the supercapacitors and Li-ion batteries. The present work investigates electrode–electrolyte interactions at the cathode using ab initio molecular dynamics simulations and representative energy-minimized ion-molecular configurations. Graphene is chosen as a material for the cathode, whereas the aqueous solutions of LiCl, NaCl, and KCl are model electrolytes. The study reveals a few fundamentally new physical insights regarding the performance of a supercapacitor. First, the graphene-ions coordination regularities are qualitatively different at charged and uncharged cathode. It is, therefore, essential to account for the effect of charging when studying the physical chemistry of supercapacitors. Second, the energy capacity offered by the aqueous Na-ion electrolyte is worse than those of the aqueous Li-ion and K-ion electrolytes. This observation is a result of an interplay between the dehydration energies and adsorption energies at the cathode energies. Third, the role of cation-solvent binding represents a cornerstone contribution to the capacity of an energy storage device in addition to the well-recognized cation-cathode binding thermodynamics. The reported results are fundamentally important to thoughtfully designing electrolyte compositions and electrode materials for supercapacitors and alkali-ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Manipulating anions to obtain the novel LiOTf-based LHE with excellent properties. • LHE enables hybrid capacitor with high voltage and good rate capability. • Hybrid capacitor realized long cycling by LiOTf derived aqueous CEI. • EQCM-D, XPS and FIB-SEM results reveal the generation and composition of CEI. Aqueous electrochemical energy storages have multiple advantages especially safety performance in the energy storage process. The high concentration aqueous electrolytes with a wide electrochemical stable voltage window (ESW) solves the key problems of aqueous electrochemical energy storages. It effectively breaks the limitation of H 2 O molecule decomposition to realize aqueous electrochemical energy storage with high operating voltage. However, the slow ion transport and high cost limit their application in power-type storages. Here, the lacked H-bond aqueous electrolyte (LHE) is proposed by investigating the structures and properties of aqueous electrolytes with various chaotropic anions. The LHE achieves high conductivity, low viscosity, and low cost while ensuring a wide ESW. These excellent properties originate from the OTf− effect on the solvation structure of cations and the number of H-bonds. An aqueous Li-ion hybrid capacitor (LHC) with the LHE exhibits high operating voltage of 2.5 V and high ESW utilization of 92.6 %. The aqueous cathode electrolyte interphase formed by anions on the cathode surface also achieved a long cycle life for the LHC. It has guided the development of novel electrolytes for electrochemical energy storage. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach for automated state of health estimation that offers similar advantages to the adaptive methods without being computation intensive. The onboard diagnosis uses a look-up table compiling the evolution of selected features of interest under any possible degradation paths. The look-up table is built from simulations of the impact of degradation on the cell electrochemical behavior. This multi-step method only requires intensive calculations prior to deployment. This approach is validated by experimental data from cells that underwent normal aging as well as plating and overcharge. Additional validation via modeling showed that the method is able to diagnose cells undergoing any degradation scenario automatically in close to 90% of cases. [ABSTRACT FROM AUTHOR]

Overheating in the joining process to create Li-ion battery cells can lead to degradation of the cells an has to be avoided; moreover temperatures lower than 0°C can lower the energy output of the cells. To avoid these issues Fraunhofer has designed a battery concept for EV-applications with a storage of the cells in a phase change material (PCM) in smaller leakage-free sub-units to buffer heat. Cu current collectors are welded in overlap on the negative pole - the top of the battery can, which is made of nickel-plated DC04 steel. The cells are welded in charged and filled state, so the the cathode and anode material, the separator and the liquid electrolyte are already inside the cell. Another function of the Cu collector is the encapsulation of the PCM, therefore the weld must be liquid-tight. The laser microwelding process of the Cu connector and 18650 cells is analysed to describe the influence of process parameters (laser power, welding speed, spatial power modulation) on the resulting connection. The characterization of the joint is performed regarding tightness, electrical resistance, mechanical stability and possible damage to the cell. [ABSTRACT FROM AUTHOR]

Efficient management through monitoring of Li-ion batteries is critical to the progress of electro-mobility and energy storage globally, since the technology can be hazardous if pushed beyond its safety boundaries. Battery management systems (BMSs) are being actively improved to reduce size, weight, and cost while increasing their capabilities. Using power line communication, wireless monitoring, or hybrid data links are one of the most advanced research directions today. In this work, we propose the use of radio frequency (RF) transceivers as a communication unit that can deliver both wired and wireless services, through their superior analog and digital signal processing capability compared to PLC technology. To validate our approach computational simulation and empirical evaluation was conducted to examine the possibility of using RF transceivers on a direct current (DC) bus for wired BMS. A key advantage of this study is that it proposes a flexible and tested system for communication across a variety of network scenarios, where wireless data links over disrupted connections may be enabled by using this technology in short-range wired modes. This investigation demonstrates that the IEEE 802.15.4-compliant transceivers with operating frequencies of 868 MHz and 2.4 GHz can establish stable data links on a DC bus via capacitive coupling at high data rates. [ABSTRACT FROM AUTHOR]

Abstract: A high-energy-density hybrid electrochemical capacitor (HEC) has been developed. The advanced HEC has graphitizable carbon activated with KOH (KOH-activated soft carbon) for the positive electrode instead of activated carbon, which is used in a conventional HEC or an electric double-layer capacitor (EDLC). The KOH-activated soft carbon had low electrostatic capacitance due to its small specific surface area in the initial state; however, the capacitance increased significantly by the first charging at potential over 4V versus Li/Li+ and exceeded the capacitance of activated carbon. The resulting capacitance was affected by the type of anion species and organic solvent of the electrolyte. In charge–discharge tests using various kinds of electrolytes, the KOH-activated soft carbon showed the best performance in the electrolyte of LiPF6 dissolved in a binary solvent composed of ethylene carbonate (EC) and dimethyl carbonate (DMC). The advanced HEC using KOH-activated soft carbon for the positive electrode gave about 8.5 times the energy density of the conventional EDLC. [Copyright &y& Elsevier]

Abstract: Two 100kWmin−1 (1.67kWh−1) Li-ion battery energy storage systems (BESS) are described. The systems include a high-power Li-ion battery and a 100kW power conditioning system (PCS). The battery consists of 12 modules of 12 series-connected Saft Li-ion VL30P cells. The stored energy of the battery ranges from 1.67 to 14kWh−1 and has an operating voltage window of 515–405V (dc). Two complete systems were designed, built and successfully passed factory acceptance testing after which each was deployed in a field demonstration. The first demonstration used the system to supplement distributed microturbine generation and to provide load following capability. The system was run at its rated power level for 3min, which exceeded the battery design goal by a factor of 3. The second demonstration used another system as a stand-alone uninterrupted power supply (UPS). The system was available (online) for 1146h and ran for over 2min. [Copyright &y& Elsevier]

The high voltage spinel material LiMn1.5Ni0.5O4 (LMNO) has the potential to increase the energy density of lithium batteries. However, its battery performance suffers from poor long-term cycling and high-temperature stability. In order to overcome these limitations, we have studied the effect of partial substitution of Mn with Ti and LiMn1.5−x Ni0.5TixO4 (x = 0.05, 0.1, 0.3), LMNTO, materials have been synthesized in a newly modified sol-gel method and then characterized by TEM, SEM (EDX), AC Electrochemical Impedance Spectroscopy and Soft X-ray Spectromicroscopy. We have demonstrated that the long-term cycling limitation with these types of materials can be resolved and herein 2000 cycles at a high C-rate have been demonstrated in half cells. We have attributed this behavior to a possible charge compensation mechanism as evidenced by a Soft X-ray Spectromicroscopy study of delithiated LMNTO materials. This work takes high energy density batteries based on high voltage spinel material one step further towards commercialization, and it is believed that further improvement can be achieved using new electrolyte formulations. [ABSTRACT FROM AUTHOR]

In this paper, a distributed energy storage design within an electric vehicle for smarter mobility applications is introduced. Idea of body integrated super-capacitor technology, design concept and its implementation is proposed in the paper. Individual super-capacitor cells are connected in series or parallel to form a string connection of super-capacitors with the associated management unit to form a panel. These super-capacitor panels are shaped to fit the alternative concept of vehicle design, and it solves the design issues and prepares for configurable electric vehicles. Body integration of super-capacitors enhances the acceleration, and regenerative braking performances of the electric vehicle increases the operating life of the Li-ion battery and improves space utilization by giving more area for the main energy source, the Li-ion battery. Integrating super-capacitor into the car body involves special packaging technology to minimize space and promotes distributed energy storage within a vehicle. This pioneering design encourages future configurable electric vehicles. Model of both the Li-ion battery and the super-capacitor employed is studied with its series internal resistance determined at various C-rates. Loss and the efficiency analysis of the bi-directional converter, traits of body integrated super-capacitors system and control of the interleaved bi-directional converter to regulate the power-sharing in the hybrid energy storage system is presented. [ABSTRACT FROM AUTHOR]

As wind energy increases its global share of the electrical grid, the intermittency of wind becomes more problematic. To address the resulting mismatch between wind generation and grid demand, long-duration (day-long) low-cost energy storage is offered as a potential solution. Lithium-ion (Li-ion) storage is an obvious, well-developed candidate, but it is currently too expensive for such long-duration applications. Liquid metal battery (LMB) storage offers large cost reductions and recent technology developments indicate it may be viable for MW-scale storage. Accordingly, we investigate co-locating and integrating LMB and Li-ion storage within the substructure of an offshore wind turbine. Integration allows the substructure to cost-effectively double as a storage container and allows for costly electrical farm-to-shore connections to be reduced to near the average power size (by reducing peak power). These benefits are compared to the costs for battery integration. Simulations show that line size can be reduced by 20% with 4 h of storage or by 40% with 12 h of storage, with negligible capacity factor losses. However, with 24 h of average power storage using LMB, no line size reduction provided the best overall net value of the turbine-storage system due to the ability to capture all available wind energy and profit from energy arbitrage and full capacity credit. In general, LMB integrated storage results in an increased relative value with current system costs. Projected technology trends indicate that these benefits will significantly improve and that integrated Li-ion storage will also become cost-effective. [Display omitted] • Low-cost, long-duration energy storage is needed for renewable energy integration. • Liquid metal battery storage may be preferred option over Li-ion storage. • Integrating battery directly into offshore wind turbine has potential cost savings. • Electrical line sizes can be reduced by 20% with 4 h of storage capacity. • Simulations of offshore wind turbine integrated with storage indicate net benefit. [ABSTRACT FROM AUTHOR]

Li‐ion hybrid supercapacitors (Li‐HSCs) hold great promise in future electrical energy storage due to their relatively high power and energy density. However, a major challenge lies in the slow kinetics of Li‐ion intercalation/extraction within metal‐oxide electrodes. Here, it is shown that ultrafast charge storage is realized by confining anatase TiO2 nanoparticles in carbon nanopores to enable a high‐rate anode for Li‐HSCs. The porous carbon with interconnected pore walls and open channels not only works as a conductive host to protect TiO2 from structural degradation but also provides fast pathways for ion/electron transport. As a result, the assembled cells exhibit remarkable rate capabilities with a specific capacity of ≈140 mAh g−1 at a slow charge and ≈60 mAh g−1 at a 3.5 s fast charge. While the charge/discharge process can be completed as fast as that of state‐of‐the‐art electrical double‐layer capacitors (EDLCs), the produced nanocomposites show three to seven times higher volumetric capacitance than activated carbons used in commercial EDLCs with acetonitrile‐based electrolytes. Equally important for some applications in cold climates or the space, the Li‐HSCs can operate at subzero temperatures as low as −40 °C, which is likely only limited by thermal properties of the acetonitrile (melting point of −45 °C). [ABSTRACT FROM AUTHOR]