High Energy Storage Density Research Articles

Engineering Maxwell–Wagner relaxation and interface carrier confinement in Al2O3/TiO2 subnanometric laminates for high-density energy storage applications

Enhanced interface confined carrier relaxation and transport in an Al2O3/TiO2 nanolaminate, from a suitable combination of sublayer and cap layer thicknesses, is promising for high density energy storage applications.

Achieving outstanding energy storage behaviors via combinatorial optimization design in BNT-based relaxor ferroelectric ceramics under medium–low electric fields

We have successfully achieved high energy storage density and efficiency under low electric fields through the compositional synergetic design of a ternary solid solution system, Bi0.5Na0.5TiO3–BaZr0.3Ti0.7O3–NaNbO3.

Achieving high energy storage density at low operating fields in lead hafnate-based novel perovskite solid solutions

Schematic diagram illustrating the concept, approaches and goal in the design and preparation of a new solid solution system (1 − x)PbHfO3–xAgNbO3, with enhanced maximum polarization and recoverable energy storage density at low operating fields.

A nonsolvolytic fluorine/LiNO3-containing electrolyte for stabilizing dynamic interfaces in Li||LiMn2O4 batteries.

Mn-based high voltage cathodes, e.g., spinel LiMn2O4, are considered among the most promising materials for cost-effective, next generation energy storage. When paired with a Li metal anode, secondary batteries based on Li||LiMn2O4 in principle offer a straightforward, scalable approach for achieving cost-effective and high energy density storage demanded in applications. In practice, however, such batteries fail to live up to their promise. Rapid capacity fading caused by irreversible Mn dissolution at the cathode coupled with mossy/dendritic Li deposition at the anode limit their useful life. In this study, we report on the design of electrolytes based on a binary blend of two widely available salts, LiNO3 and LiTFSI, in ethylene carbonate (EC), which simultaneously overcome failure modes at both the cathode and anode of Li||LiMn2O4 batteries. The electrolyte design is motivated by a recent finding that compared with their linear counterparts (e.g., dimethyl carbonate), cyclic carbonates like EC dissolve considerably larger amount of LiNO3, which markedly improves anode reversibility. On the other hand, it is known that nonsolvolytic fluorine-containing Li salts like LiTFSI, lowers the electrolyte's susceptibility to solvolysis, which generates HF species responsible for Mn leaching at the cathode. In particular, we report instead that fluorine groups in the TFSI salt, promote formation of a favorable, fluorine-rich interphase on the Li metal anode. Electrochemical measurements show that the electrolytes enable remarkably improved charge-discharge cycling stability (>1000 charge-discharge cycles) of Li||LiMn2O4 batteries. In-depth atomic-resolution electron microscopy and X-ray/synchrotron diffraction experiments reveal the fundamental source of the improvements. The measurements show that crystallographic degradation of Mn-based cathodes (e.g., surface Mn leaching and bulk defect generation) upon cycling in conventional electrolytes is dramatically lowered in the LiNO3 + LiTFSI/EC electrolyte system. It is shown further that the reduction of Mn dissolution not only improves the cathode stability but improves the reversibility of the Li metal anode via a unique re-deposition mechanism in which Li and Mn co-deposit on the anode. Taken together, our findings show that the LiNO3 + LiTFSI/EC electrolyte system holds promise for accelerating progress towards practical Li||LiMn2O4 batteries because it stabilizes the dynamic interfaces required for long-term stability at both the Li anode and the LiMn2O4 cathode.

Electrolyte tuning with low concentrations of additive for dendrite suppression in lithium metal anodes

Lithium metal is considered as an ideal anode for high-energy density storage systems with dendrites being a major issue for lifetime and safety. A gadolinium additive is found to be suppressing dendrite growth resulting higher performance retention.

Carbon Dioxide Energy Storage --- a Novel Energy Storage Technology

Carbon dioxide energy storage (CES) is a novel energy storage developed from compressed air energy storage (CAES), which is suitable for construction of large-scale long-time energy storage systems and demand for sustainable development. Its high energy storage density, low economic cost, and negative carbon emissions make this system could be widely employed. The working principle of the typical CES systems is introduced in this paper. It also discusses the principle of three types of CES systems: Thermo-electrical CES (TE-CES), trans critical and supercritical CES technology, and liquid CES technology. Additionally, two calculation indicators are introduced to depict the relationship between the energy release and storage processes, and show how much energy can be stored in one unit of storage space by the energy storage system, respectively. Finally, it discusses the applications and prospects of the CES system. According to the research, the CES system could be utilized in many fields to provide great operation efficiency and be combined with other technologies to increase reliability and availability.

Faz Değişim Malzemesi Olarak Parafinin Bir Batarya Termal Yönetim Sisteminin Soğutma Performansı Üzerindeki Etkisinin Deneysel Olarak İncelenmesi

Internal combustion engines (ICEs) are largely dependent on fossil fuels, and both the risk of depletion of fossil fuels and the harmful exhaust emissions emitted by ICEs have led researchers to become interested in electric vehicles (EVs). As the EV industry develops day by day, battery thermal management systems (BTMS) have become indispensable in solving the high-temperature problem of batteries, which are the most important component of EVs. The cost and reliability of electric vehicles are affected by parameters such as the life cycle, capacity, charging time, durability, and warranty cost of the battery pack used. The heat produced in the battery pack is removed by gas or liquid cooling in active cooling, and by phase change materials (PCM) in passive cooling. The high energy storage density of PCMs and the fact that there is no need for fan or pump power in cooling using PCMs are some of the reasons why PCMs are preferred for BTMSs. In this study, a battery pack consisting of 18 lithium-ion batteries, 6 in series and 3 in parallel, was first charged and discharged without any cooling system and then with the addition of PCM at a current strength of 1C, and the effect of the BTMS was examined. It has been observed that the BTMS has a positive effect of approximately 8% for charging experiments and 23% for discharge experiments in terms of the maximum temperature value in the battery pack.

Improved energy storage density in La-doped PbZr0.95Ti0.05O3 films with stress regulation

The Pb1–1.5xLaxZr0.95Ti0.05O3 films with different La3+ contents were successfully prepared on the LaNiO3/SiO2/Si substrates by sol-gel method. The effect of La3+ doping on the microstructure, electrical properties, and energy storage performance of the films are systematically investigated. It is found that the introducing of La3+ with a smaller tolerance factor could enhance the lattice distortion and compressive stresses, leading to smaller grain size, slimmer electric hysteresis loops, and lower phase transition field hysteresis. As a result, a relatively high energy storage density of 30.2 J/cm3 together with the energy storage efficiency of 62.2% has been achieved in Pb0.82La0.12Zr0.95Ti0.05 antiferroelectric thin films with the optimum doping content. This improvement is largely attributed to the enhanced breakdown field strength from 1442 kV/cm to 1564 kV/cm as a result of grain size reduction. Our results demonstrate the crucial role of decreased tolerance factor in stabilizing the antiferroelectric phase and enhancing the phase transition electric field, and provide an effective route to enhance the energy storage performance of antiferroelectric thin films.

Current Situation and Engineering Application Prospect of Liquid Air Energy Storage Technology

Liquid air energy storage (LAES)technology is a new-coming energy storage method using cryogenic technology as basic theory. It managed to reach consumption of new energy in a grid-connected way, absorbing low power properly, and stable output of many other forms of energy like industrial gas and electricity. This paper introduces the technical principle and advantages of LAES, analyzes and discusses the problems faced by the development of LAES technology and the corresponding solutions, summarizes the applied fields of LAES technology. It also looks forward to the development direction of LAES technology. LAES has the advantages of high energy storage density and low storage pressure, and is less restricted by geographical conditions. It can store the remaining or discontinuous power for a certain time and produce stable power output. LAES technology has a wide range of application prospects in the power system, providing a variety of energy storage services and market opportunities for the power system, the industrial field, providing a variety of energy recovery, peak-valley balance, emergency backup and energy conversion services for industrial production, and urban gas systems, providing a variety of energy reserve, peak load emergency, emergency backup and auxiliary services for urban gas systems. It is of great significance to improve the phenomenon of "wind abandonment" and "light abandonment" in the power generation industry and meet the demand of "peak cutting and valley filling" in the power grid system.

CuS loaded on reduced graphene oxide prepared by ball milling method as cathode material for high- power aqueous Cu-Al hybrid-ion batteries

Aqueous hybrid-ion batteries (AHBs) are a potential low-cost, high safety, high operating voltage and high energy density storage devices. A new type of AHBs was proposed. We use a simple, low-cost and energy-saving ball milling method for the synthesis of material that CuS anchored on reduced graphene oxide (CuS@rGO). Aqueous Cu-Al hybrid-ion batteries were prepared with CuS@rGO as cathode, Cu as anode and LiCuAl (LiCl, CuCl and AlCl3) aqueous solution as electrolyte. The battery produces a reversible capacity of 218.9 mAh g−1 at 2 A g−1. At a high current density of 5 A g−1, the capacity can also reach 166.7 mAh g−1 and the battery capacity retention rate is as high as 80 % after 500 cycles. The successfully prepared CuS@rGO has excellent rate capability and strong cycling stability at high current density, which exceeds most reported aqueous and nonaqueous systems of Aluminum-ion batteries. The introduction of reduced graphene oxide (rGO) can accelerate the electron transfer in composites and provide better electrochemical kinetics, so it is conducive to the rapid storage of aluminum ions.

Mesoscopic conductivity and trap distribution characteristics in the interfacial region of polypropylene/MgO nanocomposites with high energy storage density

Polymer dielectric materials are crucial for storage devices in power and electronic systems, as well as electric vehicles, due to their high energy density and fast discharge rates. Polymer nanocomposites (PNCs) possess superb electrical and energy storage properties, making them highly promising as next-generation thin-film dielectrics for energy storage. The excellent performance of PNCs derive from the interfacial region introduced by nano-doping. However, the current measurement equipment and technology make it difficult to accurately obtain the mesoscopic scale distribution characteristics of the conductivity of the interfacial region, and are also impossible to clarify the formation mechanism of deep traps in the interfacial region. We employed high-throughput simulation and experiment to investigate the mesoscopic conductivity and trap distribution properties of the interfacial region in PNCs. Furthermore, we developed a three-dimensional mesoscopic conductivity distribution simulation model of PNCs containing polymer matrix, nanoparticles, and interfacial region. The interfacial region size and conductivity distribution of the PNCs were determined by comparing with the experimental results, and the mesoscopic distribution characteristics of the interfacial traps in PNCs were obtained. It is proved that the nanofillers form a condensed structure with high order and compactness by restraining the movement of molecular chains, which deepens the trap energy in the interfacial region and restricts the free volume expansion. This results in the formation of interfacial regions with low conductivity, contributing to enhancing energy storage performance.

Achieving high energy storage performance in Na0.5Bi0.5TiO3‒based ceramics via Li+ substitution

In the search for dielectric material with high energy storage density, a ceramic system of 0.8Na0.5Bi0.5TiO3–0.2K1-xLixTaO3 (NBT-KLT-x, x = 0.1–0.5) is proposed in this work. The addition of Li2CO3 is conducive to the decrease of sintering temperature of ceramics. Moreover, the XRD diffraction data of sintered ceramics indicate that pure perovskite phase showing the pseudo-cubic structure can be achieved when x = 0.1–0.3 while the excessive addition of Li2CO3 leads to the formation of pyrochlore phase. Based on the Rietveld refinement and Raman results, the Li+ doping in the NBT-KLT-x solid solutions (x = 0.1–0.3) can improve the phase content of P4bm, induce the lattice expansion and structural change towards a higher-symmetry phase. TEM observation also demonstrates the reduction in the size of polar nanoregions. With increasing x from 0.1 to 0.5, both the oxygen vacancy concentration and grain size display a tendency to decrease first and then increase. For the x = 0.2 ceramics with the lowest oxygen vacancy concentration and grain size, the largest electrical breakdown strength and lowest polarization hysteresis are achieved, giving an excellent recoverable energy storage density of 4.86 J/cm3 under 32 kV/mm, accompanied by a high efficiency of 90.46 %. Additionally, the recoverable energy density achieves a high level of ∼3.5 J/cm3 and energy storage efficiency is larger than 80 % over 28–160 °C, suggesting the outstanding temperature stability.

Construction of sandwich‐layered polyimide hybrid films containing double core–shell structured fillers for high energy storage density

AbstractThe inherent low dielectric constant of polyimide (PI) dielectrics restricts their applications to become a component of high energy density film capacitors. In this work, double core–shell structured barium titanate@magnesium oxide@polydopamine (BaTiO3@MgO@PDA) nanoparticles were synthesized successfully and utilized as high dielectric constant functional fillers for PIs, in which the insulating MgO layer meliorated dielectric constant difference between BaTiO3 and PI matrix, and the organic PDA layer improved the compatibility between the inorganic fillers and PI matrices. Then, a series of sandwich‐structured PI‐based hybrid films was prepared through a layer‐by‐layer solution casting method. The middle layer of pure PI with excellent insulating properties effectively suppressed charge injection. With the combination of sandwich structure and the BaTiO3@MgO@PDA nanoparticles, the PI hybrid film containing 15 wt% fillers in the outer layers achieved the maximum breakdown strength of 425.68 kV/mm and the maximum energy density of 5.132 J/cm3, which was 68.3% and 413% higher than those of pure PI film, respectively, meanwhile maintained a low dielectric loss value of 0.0083 at 1 kHz. The introduction of BaTiO3@MgO@PDA enhanced the interfacial polarization due to the high barrier energy between adjacent layers preventing the transfer of electrons and weakening the leakage current in the sandwich‐structured composite film. This work demonstrates that an appropriate combination of high dielectric hybrid fillers and multilayer structure can effectively increase the energy storage density of PI substrate for high‐temperature energy storage applications.Highlights The double core–shell structured BaTiO3@MgO@PDA was synthesized successfully. The sandwich‐structured hybrid films were prepared by layer‐by‐layer method. The energy density of hybrid films reached a high value of 5.132 J/cm3.

Compact, efficient, and affordable absorption Carnot battery for long-term renewable energy storage

The growing penetration of renewable energy poses significant challenges to the stability of the power grid, necessitating the development of advanced energy storage systems to facilitate power grid decarbonization with enhanced flexibility. Nonetheless, current energy storage technologies face obstacles including geographical constraints, high expenses, and short lifespans. In this work, a novel Carnot battery (power-heat-power conversion) based on absorption-desorption processes of hygroscopic salt solutions, absorption Carnot battery (ACB), is proposed for large-scale renewable energy storage with remarkable energy storage density (ESD), competitive round-trip efficiency (RTE), and negligible self-discharging rate (SDR). Through the integration of heat-generation, heat-storage, and power-generation sub-cycles into a single compact system, the ACB can save space and cost compared to previous Carnot batteries. A dynamic model is established with high accuracies to explore the characteristics of the proposed system. The dynamic temperatures, pressures, concentrations, mass flow rates, powers, and efficiencies of the ACB are analyzed to elucidate its energy conversion/storage mechanism. Based on the multi-objective optimization, the optimum operating concentration range of [45%, 60%] is determined, demonstrating the best comprehensive performance with an RTE of 45.80% and an ESD of 16.26 kWh/m3. Compared to the existing energy storage systems, the ACB stands out due to the competitive RTEs (30.5%–48.4%) and higher ESDs (7.6–21.8 kWh/m3). Even during an 80-day standby period, the ACB exhibits a small SDR of only 0.74%, which is significantly lower than that of Rankine pumped thermal energy storage (RPTES) at 33.01%. Despite the ACB yields a higher initial cost, it demonstrates a markedly lower levelized cost of storage (0.342 $/kWh) compared to the RPTES (0.749 $/kWh) because of its higher ESD, thus confirming the economic feasibility of the proposed system.

From High-Throughput Experimentation to Data-Driven Analysis in the Development of Liquid Electrolytes for Lithium-Ion Batteries

Lithium-ion batteries (LIBs) are considered one of the best candidates to meet the skyrocketing demand for high energy density energy storage systems that was sparked by increasing popularity of portable electronics, electro-mobility and the necessary shift towards renewable energy sources.1 While the demand for energy storage systems rises rapidly, research moves forward rather sluggishly due to the complex interplay between the various active and inactive materials of a battery. One of the bottlenecks is the large time requirement and limited knowledge gain of typical, sequential experiments where one experiment is performed after the other. To mitigate this limitation, high-throughput experimentation (HTE) setups have been designed, where multiple experiments are performed in parallel rather than in sequence. Although they are common in other fields of research, high-throughput methods have not been widely adopted in battery research yet.2 Nevertheless, once a HTE setup is established, the bottleneck tends to move from the experiment to the data processing and analysis. Suitable tools to circumvent this are modern machine learning (ML) techniques, recognized as invaluable tools for accelerated material development. In most studies conducted for LIBs, only a limited number of electrolyte formulations is considered for a given set of individual electrolyte components due to aforementioned limitations of experimental capabilities. In this work, we have employed a unique HTE setup that is capable of applying electrochemical impedance spectroscopy (EIS) to 96 liquid electrolytes in a broad temperature range in parallel to study one of the fundamental bulk properties of liquid electrolytes; the ionic conductivity.Two large datasets of ionic conductivities were acquired for electrolytes consisting of lithium hexafluorophosphate (LiPF6), ethylene carbonate (EC), ethyl methyl carbonate (EMC) and either vinylene carbonate (VC) or propylene carbonate (PC) in the temperature range of -30 to 60 °C. Conducting salt concentration as well as solvent ratios were varied in wide ranges and experimental results bundled with all necessary metadata in an in-house developed .json file format for each individual experiment. More than 5000 individual conductivity values have been determined for 128 different electrolyte formulations in total. The conductivity datasets were used by our project partners in different ML approaches. Linear and Gaussian process regression were used to unravel the impact of individual electrolyte components on the ionic conductivity.3 Symbolic regression was used to discover an equation that directly models the conductivity based on the electrolyte formulation and has some common features with the empirical Debye-Hückel-Onsager equation.4 Active learning was used to improve an initial predictive model with as little additional experiments as possible in order to generate an accurate model for a given dataset.5 The presented work serves as a proof of concept in a system where the relation between parameters and observable are comparatively simple and is the foundation for applying similar principles of data processing, metadata handling and ML application to more complex experiments like galvanostatic cycling.

Development of Anode-Free Lithium Metal Batteries

The continuous demand for high energy density storage devices, researchers has focused on a new energy storage system for their practical life. Absolutely, Lithium metal is a best anode candidate for high energy density Lithium Metal Battery (LMB) because it has high theoretical capacity, light weight and much lower negative reduction potential.However, the growth of Li dendrite and low Coulombic efficiency upon Li plating/stripping causes the safety issues and poor cycle life of LMBs because of challenges embedded from the interaction of the Li metal with electrolyte and unstable SEI layer formation. For that reason, people have focused on developing new chemistry/system to improve the energy density, cycle life and safe energy storage system for practical applications. Anode free lithium metal battery (AFLMB) is one of the alternate choices and new system for high energy density storage system because it has no active anode material initially. In addition, the fabrication of AFLMB is simple, low-cost, safe since Li metal is not directly used as an anode. However, since the Li amount is limited and electrolyte decomposition, consuming Li during the SEI formation, the capacity can fade quickly relative to LMB. The dead Li can affect the Coulombic efficiency, polarization, and cycle life of the cell during continues cycles of AFLMB. However, AFLMB is the best system to understand the detail chemistry like quantification of dead Li, polarization effect, electrolyte consumption easily compared to the LMB. In this presentation, various approaches including functional electrolytes and functional coating on Cu surface will be reported to improve the coulombic efficiency, energy density and cycle life for the AFLMB.

(Invited) SiO and LiNi0.5Mn1.5O4 Composite Electrodes with Functional Polymer Binders

This study focuses on the optimization of polymer binders in lithium-ion batteries (LIBs) to facilitate the development of high-energy-density storage devices. Despite 30 years of commercialization, the demand for high energy density storage devices has continued to increase, making LIBs a topic of significant research interest. One major avenue of research has focused on high-voltage positive electrode materials such as LiNi0.5Mn1.5O4 (LNMO) and high-capacity negative electrode materials like SiO. However, the practical use of these materials is hindered by issues associated with electrolyte decomposition and large volume changes during the charge-discharge process.To address these challenges, we explored the chemistry of polymer binders blended in composite electrodes to maintain the structure of the electrode and form a passivation/protective layer on the active material surface to suppress side reactions.(1, 2) In particular, we investigated the use of "functional binders" to improve the performance of high-voltage LNMO composite electrodes. We synthesized sulfated alginate binders, which are significantly cheaper and stiffer than commonly used poly(vinylidene fluoride) (PVdF) and uniformly cover the surface of LNMO.(3)The high polarity of the sulfate group also increased the binder's affinity for the electrolyte. During the initial charge-discharge cycle, the electrolyte decomposition products generated on the alginate-covered active materials participated in the formation of a protective passivation layer that suppressed further decomposition during subsequent cycles, resulting in enhanced cycling and rate performances.We also explored the use of partially-neutralized crosslinked sodium polyacrylate (CLPA) binders with flexible monomers to mitigate the effects of volume changes in SiO electrodes.(4)Additionally, we investigated the “maturation” effects on battery performances by storing the composite electrodes with CLPA-based binders in a humid atmosphere for a few days before drying. Our results show that the binder with 20% flexible monomer (CLPA-20) exhibited the highest peel strength and long-term cyclability, and the maturation treatment further improved these properties. Cross-sectional SEM images revealed that the binder and conductive carbon were uniformly dispersed in the composite layer in the matured electrodes, indicating the migration of active materials and binders during the maturation process. Furthermore, surface analysis of the cycled electrode showed that the superior mechanical properties of the electrode endowed by the maturation treatment helped in maintaining the passivation layer on the active material surface, resulting in improved cycling performance.Overall, our findings suggest that optimizing polymer binders can enhance the performance of LIBs by controlling the electrode reaction via binder chemistry. The strategies developed in this study could facilitate the future development of high-energy-density LIBs, making them more accessible and commercially viable for various applications.References (1) R. Tatara, S. Komaba et al., ChemElectroChem, 8, 4345 (2021).(2) H. Isozumi, R. Tatara, S. Komaba et al., ACS Appl. Energy Mater., 3, 7978 (2020).(3) A. Oishi, R. Tatara, S. Komaba et al., ACS Appl. Mater. Interfaces, 14, 51808 (2022).(4) S. Yamazaki, R. Tatara, S. Komaba et al., Mater. Adv., 4, 1637 (2023).

In-Situ Confocal Microscopy to Analyze Volume Expansion of Solid State Microbatteries

The rise of embedded objects put great interests in miniaturized power supply solutions. Solid State Microbatteries (SSM) are the most promising, as they can safely store high energy and power density. SSM have the advantage of being all-solid (no liquid leakage and flammability), to have low self-discharge and good cyclability. Despite the strong interest in the field, the mechanisms of Li plating and stripping at the anode are not well observed and not yet fully understood [1]. The study of these phenomena would bring new insights to mechanical behavior during cycling and therefore may lead to optimization approaches at the cycle life level. In this purpose, we investigated the morphological change of SSM during the charge/discharge cycle. We looked at the influence of the cathode thickness and the packaging. Thick LiCoO2 layers were used for the study with thickness from 5 to 30 µm. Volume variations upon cycling were followed thanks to a Neox microscope 3D (Sensofar) and were correlated to charge/discharge capacity.Microbatteries are consisting of LiCoO2 (LCO) cathode and LiPON electrolyte. The anode-free configuration was adopted for integration compatibility. The anode is formed in-situ during the first charge operation. Wafers with different LCO thickness and back end level have been carried out. Confocal microscope was setup in Ar-filled glovebox to monitor the volume expansion during the charge and discharge operations. SSM cycling was operated through Biologic instruments. Figure 1 depicts a schematic representation of the SSM and the setup. Images were acquired during chrono-amperometric full charge at 4.2 V and galvanostatic full discharge at Idischarge = -3.5 µA within 3-4.2 V.Charge/discharge operations and corresponding in-situ thickness variations are presented in Figure 2 for the samples with different LCO thickness. The complete charge is achieved when current reaches a threshold of 0.5 µA. Charge capacity linearly increased with cathode thickness: Qcharge = 2.0 µA.h for the 5-µm-LCO and Qcharge = 9.6 µA.h for the 30-µm-LCO. Thickness variation increase follows the same evolution as capacity during charge and discharge. Regardless of the cathode thickness, same plating and stripping speed are observed during charge and discharge operation, respectively. According to the Qcharge and the volume variation, a theoretical lithium density at the anode side has been observed for all LCO thickness.Figure 3 depicts 2D images of 5-µm-LCO SSM at the onset of the charge. Pristine SSM presents a smooth surface (Fig. 3.a). Li plating is initiated with nucleated grains (Fig. 3.b). Then, grains grow and tend to coalesce with each other, forming a uniform and smooth Li layer (Fig. 3.c). Figure 4 reports 2D images of 30-µm-LCO SSM at different states of cycling. Bumps at the edge formed during the charge are due to SSM device architecture: electric field bends and the increased ion flux induces a more important Li accumulation on the edge. Otherwise, a uniform and fully dense Li metal deposition is realized in solid-state configuration under zero external pressure [2]. At the end of discharge, the battery thickness is higher than the pristine one (+ 3.7 µm). The Li plating non-reversibility phenomena after the first charge is due to low diffusion coefficient at low state-of-charge [3].Figure 5 shows the electrical behavior (Fig 5.a) and the volume expansion (Fig 5.b) of a SSM over 10 cycles. After the first cycle, cycling is performed at ≈100% coulombic efficiency, demonstrating high reversibility of the phenomena and so high cyclability of SSM [3].Finally, we followed the influence of the encapsulation layers on the volume variation. 2D images of the SSM reveals same volume variation for both samples. Those observations suggest that the encapsulation layers has no significant mechanical effect on the Li plating.In-situ confocal microscopy under Ar atmosphere has been proved efficient to study the volume expansion of SSM upon cycling and is a promising technique to investigate failure mechanisms of SSM.[1] J. Park et al., « In situ atomic force microscopy studies on lithium ( de ) intercalation-induced morphology changes in Li x CoO 2 micro-machined thin fi lm electrodes q », J. Power Sources, vol. 222, p. 417–425, 2013, doi: 10.1016/j.jpowsour.2012.09.017.[2] D. Cheng et al., « Freestanding LiPON: from Fundamental Study to Uniformly Dense Li Metal Deposition Under Zero External Pressure », arXiv.org, 8 août 2022. https://arxiv.org/abs/2208.04402v2.[3] J. Celè, S. Franger, Y. Lamy, et S. Oukassi, « Minimal Architecture Lithium Batteries: Toward High Energy Density Storage Solutions », Small Weinh. Bergstr. Ger., p. e2207657, janv. 2023, doi: 10.1002/smll.202207657. Figure 1

Detrimental Effects of Metal Foil’s Surface Imperfections on Metal Plating/Stripping and Facile Solutions

Rechargeable metal batteries have attracted great interest and are considered one of the most promising high-energy density storage systems. These devices benefit from the large specific volumetric capacities and high specific gravimetric capacities of metal anodes. Foils or sheets are the most common form of anode for metal batteries since they are massively manufactured and readily accessible. But short circuits from dendrites grown on metal foil anodes can dramatically decrease the cycling stability and lead to premature failure of the batteries.Homogeneous metal plating/stripping is the key to avoiding dendrite formation. And the surface uniformity of metal electrodes is crucial for the initial nucleation and growth, which greatly affects the subsequent deposition. Here, we show that manufacturing-induced defects, including surface imperfections such as a roughened surface, orange peel features, microcracks, scratches, or fold lines, and unpolished edges from cutting can all promote local dendrite growth, leading to drastically decreased cycling stability of the demonstrated Zn metal batteries and K metal batteries. Polishing the metal electrodes on both sides and edges is shown to be effective to improve the electrochemical homogeneity of the metal anode and extend the cycling lifespan by over 700% in the demonstrated Zn metal cells. Finally, we demonstrate a simple and rapid surface passivation strategy that drastically increases the tolerance of such defects in Zn metal batteries. Also, we proposed a scalable, easily automated, and facile metallic K manufacturing with robust performance in K metal batteries.Since such imperfections are ubiquitous in commercially available metal foil products. Our results remind researchers about the significant detrimental effects of these very common defects introduced by metal manufacturing and processing, which should be taken into consideration evaluating metal battery performances. Furthermore, we call for research efforts to develop effective strategies that are scalable, easily automated, and cost-effective to increase the tolerance of batteries over such defects, which will be very important for large-scale, cost-effect energy storage hubs.References Pan He and Jiaxing Huang. "Detrimental effects of surface imperfections and unpolished edges on the cycling stability of a zinc foil anode." ACS Energy Letters, 2021,6,1990-1995.Pan He and Jiaxing Huang. "Chemical passivation stabilizes Zn anode." Advanced Materials, 2022, 34, 2109872.Pan He and Yang Xu. "Facile manufacturing potassium metal anode with robust performance". In preparation. Figure 1

Performance investigation of solar-assisted supercritical compressed carbon dioxide energy storage systems

Energy storage technology plays a vital role in realizing large-scale grid connection of renewable energy. Compared with compressed air energy storage system, supercritical compressed carbon dioxide energy storage (SC-CCES) system has the advantages of small size and high energy storage density. In this paper, two solar-assisted supercritical compressed carbon dioxide energy storage (SASC-CCES) systems are proposed. One is coupled with simple regenerative compression cycle (SR-SASC-CCES), the other with recompression cycle (RC-SASC-CCES). Thermodynamic and economic analyses are carried out. The results show that the energy efficiency of the system is higher than that of other organic working fluids when the transcritical CO2 is used as the working fluid of the bottom cycle due to the residual heat available in the energy storage system of the recompression cycle. Compared with the baseline SASC-CCES system, the SR-SASC-CCES system and RC-SASC-CCES system are more conducive to improving the solar energy utilization rate, and their photoelectric conversion efficiencies are 23.56 % and 28.77 %, respectively, 2.63 % and 7.84 % higher than that of the baseline SASC-CCES system. Increasing the inlet temperature of turbine 1, energy storage pressure and energy release pressure can effectively increase the energy efficiency, solar-electricity conversion efficiency, exergy efficiency and energy storage per unit volume of these two systems. In addition, the RC-SASC-CCES system has better economic performance, whose dynamic investment recovery period is about 6.8 years. The 20-year net present value (NPV) is 23,456.16 k$, 7956.69 k$ higher than that of the SR-SASC-CCES system.