Energy Storage Techniques Research Articles

A calcium looping system powered by renewable electricity for long-term thermochemical energy storage, residential heat supply and carbon capture

Affordable long-term energy storage and CO2 capture technique are imperative to developing the future carbon–neutral energy system. This paper proposed a calcium looping system powered by excess renewable electricity to achieve long-term thermochemical energy storage, residential heat supply and carbon capture. The system can be constructed with industrial equipment and exploit natural, abundant and cheap limestone as the circulating material. The electrical calciner is designed to charge the energy and produce the high-pressured CO2 during the valley of the electricity grid, while the carbonator side is primarily driven by the discharged thermochemical energy and on-demand coordinates the heat network along with the carbon capture. The HEATSEP framework is adopted to optimize heat transfer processes and operating conditions for deriving the most favorable system configuration in the energy and economic aspects. Compared to the reference plant with electric boilers and short-term heat storage tanks, an energy penalty of around 32.3% total energy percentage points should be paid to drive long-term energy storage and carbon capture. The energy penalty is attributed to thermal losses in the calciner and heat exchanger networks, chemical energy lost by the make-up flow of fresh limestone, CO2 compression for storage and auxiliary power for solid/fluid circulations. Due to a comparable total plant investment cost to the reference plant, the proposed system achieves the CO2 avoidance cost of 111.1 RMB/tonCO2, showing some competitiveness over current post-combustion carbon capture techniques. The techno-economic competitiveness of the proposed system can be further strengthened by replacing natural or synthetic Ca-based materials with high cycling performance instead of limestone, as well as extending applicable occasions to achieve almost year-round operation.

Decorating CaO with dark Ca2MnO4 for direct solar thermal conversion and stable thermochemical energy storage

Calcium looping (CaL) process, a thermochemical energy storage technique, probably offers a mid-term if not near-term solution to the next generation Concentrated Solar Power (CSP) plants featured with high temperature over 700 °C. However, CaCO 3 used in the conventional CaL-CSP system is usually white with little absorption of sun light, hindering its application in efficient volumetric solar energy conversion scheme. This work decorates CaO with dark Ca 2 MnO 4 derived from natural manganocalcite, achieving direct solar absorption and simultaneously enhanced anti-sintering ability due to the presence of dark Ca 2 MnO 4 . As a thermal stabilizer, Ca 2 MnO 4 minimized the sintering-induced decay of the materials' energy storage density and ensured high and stable energy storage performance over prolonged operation cycles. Detailed electron microscopy-based analysis confirmed the compositional homogeneity which is identified, together with the porous structures, as the crucial feature to guarantee a stable performance. Over 20 cycles, CaO/Ca 2 MnO 4 nanoparticles still remained energy storage density of 1932 kJ/kg, exceeding that of the limestone-derived reference material by nearly 100%. Additionally, the average solar absorptance of Ca 2 MnO 4 -stabilized calcium composite is remarkably enhanced in comparison with that of conventional limestone. This work paves the way for designing materials with high energy storage density and excellent cyclic stability for simultaneous solar thermal conversion and high-temperature thermochemical energy storage. • CaO was decorated with dark Ca 2 MnO 4 by calcining natural manganocalcite. • Dark Ca 2 MnO 4 enhanced the direct solar absorption ability of CaCO 3 . • The sintering resistance of calcium composites was improved by inert Ca 2 MnO 4 support. • Dark CaO/Ca 2 MnO 4 composite achieved stable thermochemical energy storage.

Environmental trade-offs and externalities of electrochemical-based batteries: Quantitative analysis between lithium-ion and vanadium redox flow units

This study aims to increase the scientific knowledge of the environmental impacts and externalities of two promising electrochemical-based techniques for large-scale stationary energy storage: lithium nickel cobalt manganese (NCM) and vanadium redox flow (VRF) batteries. The global warming potential (GWP) and cumulative energy demand (CED) for NCM and VRF batteries are 28 kg CO2eq and 410 MJ and 186 kg CO2eq and 3080 MJ, respectively, for the provision of 1 MWh of electricity. While the trend of the environmental externality results is proportional to the environmental impact results, the environmental costs from GWP and terrestrial ecotoxicity impacts contribute the largest share of the total environmental costs for both batteries. Overall, NCM batteries have favorable environmental performance in terms of their impact values and externalities but still show relatively higher contributions in human toxicity and ozone layer depletion impacts, based on their high resource uses. The VRF batteries, on the other hand, report higher impacts in abiotic depletion, GWP and terrestrial ecotoxicity, mainly due to their great mass of the electrolyte. Our results highlight the importance of substituting the active metals with low-impact metals or carefully considering the origin of key materials while also taking advantage of the properties of the battery to carefully assess possible advancements in battery design. The environmental externality results also provide essential information for the future development of battery industries for stationary applications with energy and environmental benefits.

Thermal performance analysis and optimization of cascaded packed bed latent heat storage tank

The packed bed tank with multiple phase change materials (PCMs) is one of the most efficient latent heat energy storage techniques. This study presents insight into the influence of the latent heat arrangements on the cascaded packed bed tank, providing a new idea for designing multi-PCM packed bed tank, which concerns the screening of PCMs. In this study, a parametric study is conducted to optimize the latent heat of the multi-PCM packed bed tank for the charging and discharging process. A developed two-dimensional model is used to predict the thermal behaviors of the heat transfer fluid and PCMs in packed bed tanks, which is verified by experiment. The results showed that the case with uniform latent heat arrangement exhibits the best overall thermal performance, which obtains the lowest standard deviation of average heat-exchange zone travel velocities for the charging and discharging cycle process. Moreover, the relationship between the efficiency and the standard deviations of the heat-exchange-zone travel velocities is unearthed, and its effectiveness is verified by an actual cascaded PCMs packed bed tank. The charging/discharging/overall efficiency increases with a decrease in the standard deviation of the heat-exchange-zone travel velocities of the PCM layers. This relationship can be used as a new PCM selection method for the cascaded latent heat storage tank. In addition, the actual cascaded packed bed unit with a different latent heat is optimized by variable capsule diameters.

RESIDENTIAL SOLAR ENERGY STORAGE SYSTEM: STATE OF THE ART, RECENT APPLICATIONS, TRENDS, AND DEVELOPMENT

The use of energy storage devices is essential for the development and maintenance of zero-energy structures. They are necessary for optimal usage of renewable energy sources and for managing the intermittent nature of energy supply and demand. Many different types of storage systems (electrochemical, thermal, mechanical, etc.) are either commercially available or close to being developed for usage on a building scale. Different technologies have different capabilities and features, therefore it's important to find a system for evaluating your possibilities before diving into a techno-economic study. All aspects of current and emerging energy storage technologies, as well as their uses, future prospects, and historical contexts, are subjected to a rigorous evaluation. Energy storage techniques such as electrochemical and battery storage, thermal storage, thermochemical storage, flywheel storage, compressed air storage, pumped storage, magnetic storage, chemical and hydrogen storage, and redox flow storage are all covered. New studies on alternative energy storage methods, along with major advancements and discoveries in the field, are also discussed.

Rapid ultrasound welding toward compact Na/Beta-Al2O3 interface realizing room-temperature solid-state sodium metal battery

Interfacial regulation on Na metal/solid electrolytes benefits for realizing room temperature solid-state sodium metal battery for energy storage technique, yet remains challenging due to rigid solid-solid contact and unmanageable dendrite growth. To suit the remedy to the annoying interfacial trouble, a highly efficient ultrasound welding (UW) strategy is rolled out and successfully verified by Na/Beta-Al2O3 interface in one minute. The UW-Na/Beta-Al2O3/UW-Na symmetric cell accompanied by a critical current density of 0.65 mA cm−2 can be cycled stably for over 800 h at 0.1 mA cm−2 at room temperature. Integrating into polyanion-typed Na3V2(PO4)3 cathode with three-dimensional Na+ transport, the room-temperature sodium metal full battery delivers a high energy density of 234 Wh kg−1 under a high power density of 1773 W kg−1. Such full battery provides a reversible capacity of 86 mA h g−1 after 700 cycles at 0.5 C with a capacity retention of 86.66%. This work elucidates the atom-level ultrasonic welding strategy for constructing compact Na/Beta-Al2O3 interface, providing rational design on engineering Na/solid electrolyte interface for solid-state sodium metal battery.

Graphene–Silver Hybrid Nanoparticle based Organic Phase Change Materials for Enhanced Thermal Energy Storage

Due to the intermittent nature of solar energy, researchers and scientists are working to develop thermal energy storage (TES) systems for effective utilization of solar energy. Phase change materials (PCMs) are considered to be promising materials for TES. In this study, organic paraffin RT50 and graphene silver (Gr:Ag) nanopowder are adopted as TES material and thermal property enhancers. Microstructure and morphological behavior as well as chemical, optical, and thermal stability of the prepared composite PCM are visually investigated using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy, thermal conductivity analyzer, differential scanning calorimeter (DSC). and thermogravimetric analyzer (TGA). Furthermore, based on the outstanding thermal performance of the composite, an extended investigation on the thermal and chemical properties are evaluated for 500 thermal cycles to ensure their reliability. Results show the thermal conductivity of RT50 improved by 53.85% when Gr:Ag nanopowder is dispersed at a weight percent of 0.8 (RT50-0.8Gr:Ag). The change in latent heat value of the composite sample is less than 3%, which is significant for effective thermal energy storage. The thermal decomposition of RT50 is slightly improved from 300 °C to 330 °C. To ensure a reliable and passive technique for thermal energy storage within solar thermal application devices, such as solar air heaters and solar photovoltaic thermal systems, using nanoparticle enhanced PCMs at the range of a 50 °C melting point are a current research hotspot.

Synergy of Li2CO3 promoters and Al-Mn-Fe stabilizers in CaCO3 pellets enables efficient direct solar-driven thermochemical energy storage

Calcium carbonate (CaCO3) pellets are suitable for scalable solar thermochemical energy storage but suffer from low solar absorptance, poor stability, and slow reaction kinetics, which lead to low solar energy storage efficiency. Here, for the first time, we successfully achieve fast and efficient solar thermochemical energy storage via synergistically employing Al, Mn, and Fe stabilizers for improving both cyclic stability and solar absorptance, and Li2CO3 promoters for accelerating decomposition of CaCO3 pellets. The average solar absorptance is 1500% higher than that of pure CaCO3 pellets. After 60 cycles, the energy storage density is still as high as 1671 kJ/kg with a decay rate of only 4.14%, in stark contrast to energy density of 1121 kJ/kg and decay rate of 56.73% for pure CaCO3 pellets. The average decomposition rate is about twice as fast as that of pure CaCO3 pellets due to enhanced Ca2+ diffusion by doped Li2CO3. Under direct light irradiation, novel CaCO3 pellets demonstrate high energy storage rate due to both high solar absorptance and fast decomposition rate, while pure CaCO3 pellets cannot even reach the decomposition temperature. This work opens new opportunities for scalable deployment of direct solar-driven thermochemical energy storage techniques based on Li2CO3-doped dark CaCO3 pellets.

Constructing Nonaqueous Rechargeable Zinc-Ion Batteries with Zinc Trifluoroacetate

Rechargeable zinc-ion batteries (RZIBs) are recognized as promising alternative energy storage techniques for large-scale application. Using organic electrolytes with wide electrochemical stability windows to construct nonaqueous RZIBs enables high operating voltage and energy density. However, the selection of zinc salts with cost-effectiveness and excellent electrochemical performance for nonaqueous electrolytes is limited. In this work, the electrochemical properties of a competitive zinc salt, zinc trifluoroacetate (Zn(TFA)2), are investigated in acetonitrile and triethyl phosphate. It is found that the Zn(TFA)2 is highly soluble in the organic solvents, reaching 15 mol·kg–1 in acetonitrile. The Zn(TFA)2 electrolytes show a wide electrochemical stability window of 2.2 V, good conductivity of 6.14 mS·cm–1 at 1.0 mol·kg–1, and good compatibility with the Zn metal anode. Zn(TFA)2 tends to form ion pairs or aggregates in triethyl phosphate, which improve the electrochemical stability but partially expense the ionic conductivity. Full batteries are fabricated with the Zn(TFA)2 electrolytes using potassium manganese hexacyanoferrate as the cathode. The batteries with Zn(TFA)2-AN-TEP (19%) electrolyte deliver a high specific density of 181.9 Wh·kg–1 at 0.1 A·g–1 and excellent cyclic stability with a capacity retention rate of 71.7% after 1000 cycles at 0.5 A·g–1. Our results suggest that the Zn(TFA)2 is a promising candidate of zinc salts in the application of nonaqueous RZIBs.

Green Silicon Carbide (SiC) and SiC/Graphite Composite Anodes for Lithium-Ion Batteries

Arising from concerns of continuously deteriorating environmental issues, worldwide efforts are dedicated to developing more sophisticated energy storage techniques to replace traditional nonrenewable sources. Given the significant greenhouse gas emissions that occur coincident with current battery production and operation, the introduction of agricultural waste rice hull ash (RHA), a byproduct of biomass combustion, as a source for battery components could facilitate the actual realization of green and sustainable energy storage. Herein, we focus on using RHA to produce SiC with hard carbon (HC) nanocomposites and their mixtures with graphite as Li+ battery anodes.Using a simple method developed in our laboratories to control SiO2:HC ratios, the intrinsic nanoscale mixing of SiO2 and HC in RHA provides a natural starting material for carbothermal reduction producing high purity SiC without the need to add an external carbon source. The optimized SiC/HC nanocomposites contain ≈13 wt. % HC, showing BET surface areas >200 m2/g.We previously reported the SiC/HC nanocomposites derived from RHA exhibit charge/discharge capacities 3× of current graphite anodes at > 950 mAh g-1, accompanied by distinct capacity increases. In particular, SiC can be lithiated to Li1.1-1.4SiC without forming LixSi or LixC. Investigations of the lithiation/delithiation mechanisms using multiple techniques coupled with modeling suggest a cubic (3C-SiC) to hexagonal phase transition (6H-SiC) after long-term cycling, which may explain the origins of extraordinary capacity increments. Moreover, lithiation/delithiation occur without significant volume changes according to XRD and SEM, suggesting that SiC can compete with metallic Si as an anode material as free volumes equivalent to 3× the charged Si are required.Most recently, inspired by the developed concept of adding graphite to improve the performance of silicon-based anodes, we find adding graphite to SiC/HC nanocomposites results in a 3× improvement in capacity increases on cycling, reaching >950 mAh g-1 after 150 cycles. The proposed interactions within the composites will also be addressed in this presentation. It should be noted most silicon/graphite composite anodes use low Si contents of < 30 wt. % to limit the total electrode volume expansion and ensure contacts and conductivities between components, which restrains the practical energy density improvements from using Si in the anodes. In comparison, mixing only 30 wt. % graphite with SiC/HC in the current work results in specific capacities competitive with Si. Furthermore, Si metal can be synthesized via the carbothermal reduction at ≈1900 °C, while battery-grade graphite used today is produced in an environmentally harmful and expensive multistep method that involves heating to ≈3000 °C. The SiC/HC need only be heated to 1450 °C, with hard carbon forming coincidentally providing positive effects on anode performance. In this aspect, directly using SiC/HC or adding a low amount of graphite to further boosts its performance in an apparently more environmentally friendly route to alternative anodes.

Powering Solutions for Biomedical Sensors and Implants Inside the Human Body: A Comprehensive Review on Energy Harvesting Units, Energy Storage, and Wireless Power Transfer Techniques

For implantable medical devices, it is of paramount importance to ensure uninterrupted energy supply to different circuits and subcircuits. Instead of relying on battery stored energy, harvesting energy from the human body and any external environmental sources surrounding the human body ensures prolonged life of the implantable devices and comfort of the patients. In this article, we present existing issues and challenges related to the state-of-the-art solutions used for harvesting energy to power implantable devices. In addition, the details on existing energy storage technologies and various wireless power transfer techniques incorporating external or internal energy sources and sensors have been discussed. The authors have outlined the performance and power constraints of existing biomedical devices and provided a brief overview of various power architectures found in the literature. This survey has been conducted on existing implantable solutions in terms of output voltage, current, device dimension, application, generated power, energy density, and so on. Finally, the advantages and drawbacks of different solutions have been discussed and compared. Therefore, this article can be considered as an expedient reference for researchers conducting research in the field of energy scavenging, internal energy storage, wireless power transfer techniques, and power management of implantable medical devices.

Preparing Co/N-Doped Carbon as Electrocatalyst toward Oxygen Reduction Reaction via the Ancient “Pharaoh’s Snakes” Reaction

The oxygen reduction reaction (ORR) is of great importance for clean energy storage and conversion techniques such as fuel cells and metal–air batteries (MABs). However, the ORR is kinetically sluggish, and expensive noble metal catalysts are required. The high price and limited preservation of noble metal catalysts has largely hindered the wide application of clean power sources such as fuel cells and MABs. Therefore, it is important to prepare non-expensive metal catalysts (NPMC) to cut the price of the fuel cells and MABs for wide application. Here, we report the preparation of a Co3O4 carried on the N-doped carbon (Co/N-C) as the ORR NPMC with a facile Pharaoh’s Snakes reaction. The gas generated during the reaction is able to fabricate the porous structure of the resultant carbon doped with heteroatoms such as Co and N. The catalyst provides a high electrocatalytic activity towards ORR via the 4-e pathway with an onset and half-wave potential of 0.98 and 0.79 V (vs. RHE), respectively, in an electrolyte of 0.1 M KOH. The onset and half-wave potentials are close to those of the commercial Pt/C. This work demonstrates the promising potential of an ancient technology for preparing NPMCs toward the ORR.

Biosynthesis of zinc oxide-cobalt oxide nanocomposite as electrode material and its performance evaluation for the sustainable hybrid supercapacitor energy storage devices

Novel energy storage techniques and systems have gained increasing importance in recent times to overcome the variability in the output of non-dispatchable renewable energy sources. Supercapacitors are energy storage systems that have attracted considerable attention from various stakeholders. However, the performance of an effective supercapacitor energy storage system depends mainly on the electrochemical behavior of the electrodes, and the methods used to fabricate the electrode materials. Sustainable methods for the fabrication of electrode materials such as green synthesis have recently attracted researchers. In this work, a method is proposed to synthesize zinc oxide and cobalt oxide nanocomposite using green synthesis to take advantage of their superior electrochemical properties and stability. Evaluation of the morphological and electrochemical performance of the fabricated nanocomposite showed good results. Further, the electrode material fabricated using the synthesized nanocomposite has shown energy density values in the range of 3.8 Wh/kg to 9.54 Wh/kg for the power density values of the range 3000 W/kg to 375.3 W/kg for the different chosen current densities. A retention capacity of approximately 85% was observed even after 5000 cycles which is one of the most important features of supercapacitors. Thus, green synthesis with its intrinsic advantages over chemical methods is expected to be a promising approach for the fabrication of electrode materials for supercapacitors in sustainable energy storage applications in the future.

Facile Synthesis of FeCoNiCuIr High Entropy Alloy Nanoparticles for Efficient Oxygen Evolution Electrocatalysis

The lack of an efficient and stable electrocatalyst for oxygen evolution reaction (OER) greatly hinders the development of various electrochemical energy conversion and storage techniques. In this study, we report a facile synthesis of FeCoNiCuIr high-entropy alloy nanoparticles (HEA NPs) by a one-step heat-up method. The involvement of glucose made the NPs grow uniformly and increased the valence of Ir. The resulting FeCoNiCuIr NPs exhibit excellent OER performance in alkaline solution, with a low overpotential of 360 mV to achieve a current density of 10 mA cm−2 at a Tafel slope of as low as 70.1 mV dec−1. In addition, high stability has also been observed, which remained at 94.2% of the current density after 10 h constant electrolysis, with a constant current of 10 mA cm−2. The high electrocatalytic activity and stability are ascribed to the cocktail effect and synergistic effect between the constituent elements. Our work holds the potential to be extended to the design and synthesis of high-performance electrocatalysts.

Experimental Investigation on the Performance Characteristics of Flow Fields in Redox Flow Batteries Under Various Electrode Parameters

All-vanadium redox flow battery (VRFB) is a promising energy storage technique. Flow fields play a crucial role in distributing the electrolyte into the electrode uniformly, but their performance characteristics under different electrode parameters are still unclear. In this work, taking the total pressure drop and total overpotential as performance characterizations, the influence of electrode parameters and operating conditions on the performance of serpentine flow field (SFF) and interdigitated flow field (IFF) are experimentally investigated. It is found that the battery with IFF exhibits lower pressure drop than that with SFF because of the shunt effect of IFF on electrolyte. In terms of promoting the uniform distribution of the electrolyte into the electrode, the SFF outperforms IFF when the electrode porosity is higher than 0.810, but the performance of SFF and IFF could be reversed as the electrode porosity decreases to 0.714, indicating that there may be a performance reversal between SFF and IFF when the electrode porosity decreases from 0.810 to 0.714. Moreover, the increase of current density, the decrease of electrolyte input, and the decrease of electrode thickness strengthen the performance reversal at low electrode porosity. The results well explain the debate on the superiority of IFF and SFF and the discussion on the preference between flow fields and electrode thickness in literatures and provide guidance for the selection of optimal flow field in VRFBs.

Carbon-Based Materials as Lithium Hosts for Lithium Batteries.

Lithium (Li) metal has attracted significant attention in areas that range from basic research to various commercial applications due to its high theoretical specific capacity (3860 mA h g-1 ) and low electrochemical potential (-3.04 vs. standard hydrogen electrode). However, dendrites often form on the surfaces of Li metal anodes during cycling and thus lead to battery failure and, in some cases, raise safety concerns. To overcome this problem, a variety of approaches that vary the electrolyte, membrane, and/or anode have been proposed. Among these efforts, the use of three-dimensional frameworks as Li hosts, which can homogenize and minimize the current density at the anode surface, is an effective approach to suppress the formation of Li dendrites. Herein, we describe the development of using carbon-based materials as Li hosts. While these materials can be fabricated into a variety of porous structures, they have a number of intrinsic advantages including low costs, high specific surface areas, high electrical conductivities, and wide electrochemical stabilities. After briefly summarizing the formation mechanisms of Li dendrites, various methods for controlling structural and surface chemistry will be described for different types of carbon-based materials from the viewpoint of improving their performance as Li hosts. Finally, we provide perspective on the future development of Li host materials needed to meet the requirements for their use in flexible and wearable devices and other contemporary energy storage techniques.

Solid-state electrolytes for beyond lithium-ion batteries: A review

Safe energy storage technique is prerequisite for sustainable energy development in the future. Designing Solid-State Electrolytes exhibiting high ionic conductivity, good electrochemical performances, high mechanical/thermal stability, compatible electrolyte/electrode interface is the main concern for developing the next-generation rechargeable batteries. This review presents the state of the art of Solid-State Electrolytes for beyond lithium-ion batteries, mainly, for Sodium-ion batteries, Potassium-ion batteries, Calcium-ion batteries, Magnesium-ion batteries, Zinc-ion batteries, and Aluminum-ion batteries. The main aspects of SSEs, including the synthesis processes, the physico-chemical properties, and the electrochemical performance, are emphasized.

Construction of Hybrid Coating Layer for Robust Zinc Anodes

The environmental pollution and energy crisis require the development of large-scale energy storage techniques. Batteries have attracted enormous attention over the past several years due to their relatively long cycle life and high energy density . Lithium-ion batteries as the most widely used energy storage devices still have safety hazards, high cost issues. Zinc-based rechargeable batteries, have gained remarkable attention as a promising energy storage technology, especially in mild/neutral aqueous electrolytes. Aqueous zinc-ion batteries are promising candidates for the next-generation energy storage system. Zinc metal anode exhibits high theoretical capacity (820 mA h g-1), low redox potential (-0.76 V vs the standard hydrogen electrode), low cost, and intrinsically high safety. However, practical application limited by severe dendrite formation, corrosion and hydrogen evolution on the anode surface. They can cause low Coulombic efficiency, short cycling life and even puncture of separators or short-circuit in the batteries. One of efficient strategies toward improving reversibility of Zn anode is to use surface engineering strategies such as building an artificial coating protection layer for zinc-electrolyte interface to provide defined and smooth Zn depostion behavior. In this work, we designed and synthesized an inorganic-carbon composite protection layer by complexing zinc oxide with carbon. This composite protection layer not only effectively shields rampant electrolyte diffusion to suppress side reactions but also suppresses Zn dendrites by uniform Zn plating/stripping. Symmetric cells with hybrid coating layer show extended cycle life and small voltage polarization. Full batteries with Mn-based and V-based cathodes can be assembled with increased capacity and stable cycling performance.

(Invited) Dynamic Plating/Stripping Behavior of Zn Anode in an Operating Aqueous Zn-Ion Battery

To circumvent the fossil resource depletion and to reduce the carbon emission, electrochemical energy storage technique undergoes blooming developments over the past few decades. A promising candidate for electrochemical energy storage is the rechargeable Zn aqueous battery, which has the merits of rich Zn abundance, low cost, high safety, and environmental friendliness. Despite of enormous research and engineering investments, the practical implementation and deployment of Zn aqueous battery are still hindered by challenges concerning several different aspects of the electrochemical reaction involving Zn-ions. One of the main obstacles is that the Zn anode suffers from a low Coulombic efficiency, and the underlying mechanism is related with the non-ideal reversibility of the Zn plating/stripping process. The behavior of Zn plating and stripping is sophisticated and can be modulated by several co-existing and intertwined factors, including the electrode configurations, the charging/discharging protocols, and the composition of the electrolyte.For example, it has been demonstrated that the anode morphology can affect the dendrite growth. By fabricating Zn anode with a 3D sponge structure, the Ni-Zn cells could exhibit an improved cycle performance and a suppressed dendrite formation. Plating with high current density could exacerbate the electrochemical polarization and tends to form Zn dendrites. As a mitigation, the Zn dendrites can be dissolved by applying a small current during the stripping process. In addition, surface chemistry on anode plays a critical role in the Zn plating/stripping process. The reactions involving the solid-liquid interphase are often complicated and may vary depending on the electrolyte used. A holistic investigation of the structural, dynamic, and chemical features in Zn-ion batteries under operating conditions is key to the development of high-performance Zn-ion battery.In this talk, I will present our recent study using in-situ X-ray tomography and operando X-ray radiography to investigate the Zn plating/stripping behaviors in an in-house developed aqueous zinc-ion battery cell. We electrochemically plate Zn on a three-dimensional Cu foam and reveal how the electrode configuration and the local morphology collectively regulate the Zn plating behavior. Through advanced quantification and analysis of the tomographic data, we uncover that the Zn deposition in ZnSO4 electrolyte exhibits a substrate-curvature dependence. We further investigate how the current density would modulate the Zn plating using operando X-ray radiography. I will also briefly discuss the possibility of utilizing a novel tri-contrast x-ray imaging method to image dendric structures with better sensitivity and contrast.

Fabrication of shape-stabilized phase change materials based on waste plastics for energy storage

High value-added use of waste plastic has emerged an urgent research topic due to its heavy pollution to environment. Meanwhile, fluctuant characteristic of renewable energy leads to energy storage techniques to be always at the core of energy research. A protocol which could solve the pollution brought by waste plastics and making an energy storage material is highly meaningful. Herein, we found waste plastics could serve as a supporting material for the encapsulation of phase change material (PCMs), it would not only solve the leakage problem of PCMs in phase transition process, but also makes contribution to the problem of waste plastic pollution to the environment and ecology. Paraffin wax (PW) was used as a phase change material and encapsulated with porous carbon material which prepared from waste plastics through a vacuum absorption method. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) analysis and X-ray diffraction (XRD) analysis were carried out to study the chemical composition and microstructure on this PCMs waste plastics based thermal energy material. Thermal conductivity, phase change temperature and latent heat of PCMs were tested to understand thermophysical properties of the obtained materials. Moreover, heat storage platform was installed to further know the energy storage performance of this PCMs composite made from waste plastics.