Large-scale Energy Storage Research Articles

N-Doped Porous Carbon Based on Anion and Cation Storage Chemistry for High-Energy and Power-Density Zinc Ion Capacitor.

Zinc ion hybrid capacitors (ZIHCs) show promise for large-scale energy storage because of their low cost, highly intrinsic safety, and eco-friendliness. However, their energy density has been limited by the lack of advanced cathodes. Herein, a high-capacity cathode material named N-doped porous carbon (CFeN-2) is introduced for ZIHCs. CFeN-2, synthesized through the annealing of coal pitch with FeCl3·6H2O as a catalytic activator and melamine as a nitrogen source, exhibits significant N content (10.95 wt%), a large surface area (1037.66 m2 g-1), abundant lattice defects and ultrahigh microporosity. These characteristics, validated through theoretical simulations and experimental tests, enable a dual-ion energy storage mechanism involving Zn2+ ions and CF3SO3 - anions for CFeN-2. When used as a cathode in ZIHCs, CFeN-2 achieves a high-energy density of 142.5W h kg-1 and a high-power density of 9500.1W kg-1. Furthermore, using CFeN-2 ZIHCs demonstrate exceptional performance with 77% capacity retention and nearly 100% coulombic efficiency after 10 000 cycles at 10 A g-1, showcasing substantially superior performance to current ZIHCs. This study offers a pathway for developing high-energy and high-power cathodes derived from coal pitch carbon for ZIHC applications.

Lattice matching strategy in Cu-based oxides for large-scale and long-term thermochemical energy storage

Redox-active metal oxides, particularly Cu-based oxide, are noteworthy for their economic feasibility and potential as a recyclable, zero-carbon energy source. These materials are poised to serve as a sustainable solution for large-scale and long-term thermochemical energy storage (TCES), thereby mitigating the intermittency challenges inherent in renewable energy systems. However, a significant impediment to their performance is the materials sintering at elevated temperatures, which precipitate a decline in cyclic reversibility, often manifesting even within the initial cycle of operation. To counteract this limitation, we proposed an innovative approach that leverages the concept of lattice matching, augmented by the incorporation of cigarette butts in the synthesis process to fabricate a Cu-Ce heterogeneous interface. This matched lattice preserved the integrity of the TCES material's porous architecture. Additionally, the lattice oxygen within this composite exhibits a transferability. Even after a prolonged period of two years under ambient air conditions, the TCES material retains the capacity to discharge a remarkable 99.4 % of its adsorbed energy. Furthermore, over the course of 600 cycles, the system's stability is remarkably preserved at 98–100 %, and reversible loss of pure CuO is ∼40 % within the initial cycle. Given these attributes, this TCES material emerges as a promising candidate for industrial applications.

Ethyl Isopropyl Sulfone Modulating to Achieve Stable High-Voltage Electrolyte for Lithium-Ion Batteries.

The demand for efficient large-scale energy storage necessitates high-energy-density batteries, making research on high-voltage electrolytes particularly important. In this article, ethyl isopropyl sulfone (ES), which has a high dielectric constant, is added to traditional carbonate-based electrolyte solvents and analyzed. Based on calculated and analyzed results, different proportions of ES are added to the conventional carbonate-based electrolyte. The high-voltage performance, the influence on the surface of the electrode, the active material structure after cycling, the electrochemical behavior, and the impedance of the electrode were studied systematically. As a result, ES addition is applied in high-voltage lithium-ion batteries and exhibits excellent electrochemical properties. These results will provide support for the research and application of sulfone additives in increasing the decomposition voltage of lithium-ion battery electrolytes and improving battery cycle stability.

PEG-based co-solvent aqueous electrolytes enabling high-energy rechargeable aqueous magnesium-ion batteries

In contrast to organic electrolyte systems, rechargeable aqueous magnesium-ion batteries (RAMIBs) offer unparalleled advantages, particularly in environmental sustainability, safety, cost-effectiveness, and their potential for large-scale energy storage. However, the practical implementation of RAMIBs has been hindered by the limited electrochemical stability of aqueous electrolytes. Although polyethylene glycol (PEG)-based aqueous electrolytes provide a wide electrochemical window, the poor ionic conductivity has restricted their widespread adoption. In this study, we address this challenge by employing trimethyl phosphate (TMP) and PEG400 as the co-solvent of aqueous magnesium-ion electrolytes. This combination significantly enhances the ionic conductivity to 4.44 mS cm−1 and increases the electrochemical stability window of the aqueous electrolyte by mitigating the activity of H2O. In addition, we underscore the role of TMP as a potent co-solvent in modulating the solvation structures of Mg2+ ions and modifying the electrochemical behavior of the electrolytes. Leveraging this advancement, in conjunction with a V2O5 cathode and a 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) anode, the resulting RAMIBs demonstrate a remarkable discharge capacity of 227.6 mAh g−1, a large energy density of 157 Wh kg−1 and a high power density of 70 W kg−1. Our findings represent a significant stride toward exploiting the full potential of RAMIBs for future energy storage applications.

Revealing the intricacies of natural convection: A key factor in aqueous zinc battery design

Aqueous zinc-based batteries offer high safety, abundant resources, low cost, and environmental friendliness, making them a promising alternative to lithium-ion batteries for large-scale energy storage markets. However, the natural convection in the electrolyte during operation, which can greatly affect the battery performance, is overlooked for a long time. Through particle tracing experiments, this study demonstrates that in the vertical placement of the battery, natural convection occurs due to the variation of electrolyte density, whereas it does not happen when the cathode is on top. Besides, there is a significant difference in electrochemical performance between these two configurations, with a voltage difference of up to 0.25 V at 10 mA cm⁻² and a peak current difference of up to 3.4 mA in linear sweep voltammetry. Simulation results show that convective mass transfer can be up to 100 times greater than diffusive mass transfer in a bulk solution. This highlights the importance of considering natural convection to improve model accuracy. Further, to increase energy density, batteries are scaled up in practical applications to reduce the weight of the casing. This work simulates mass transfer conditions under various scenarios, illustrating the trade-off between current density and battery size, and offering new guidance for the design of aqueous zinc-based batteries.

Advancing Zinc Anodes: Strategies for Enhanced Performance in Aqueous Zinc-Ion Batteries.

The promising features of aqueous zinc ion batteries (AZIBs), including their inherent safety, environmental friendliness, abundant raw materials, cost-effectiveness, and simple manufacturing process, position them as strong candidates for large-scale energy storage. However, their practical application faces significant challenges, such as uncontrolled dendritic growth, undesirable side reactions, and hydrogen evolution reactions (HER), which undermine the efficiency and longevity of the system. To address these issues, extensive research has been conducted to improve these batteries' energy density and lifespan. This comprehensive review explores the fundamental mechanisms of zinc dendrite formation, its properties, and the interfacial chemistry between the electrode and electrolyte. It also delves into strategies for protecting the zinc anode, with a focus on the modulation of zinc ion deposition dynamics at the electrolyte interface. The discussion concludes with an evaluation of the current challenges and future prospects of AZIB, aiming to enhance their viability for grid-scale energy storage solutions.

Distributed Optimization Strategy for New Energy Stations and Energy Storage Stations Considering Multiple Time Scales

The “dual carbon” goal has made it a mainstream trend for new energy stations (NESs) and energy storage stations (ESSs) to jointly participate in market regulation. This paper proposes a multiple time scale distributed optimization method for NESs and ESSs based on the alternate direction multiplier method (ADMM). By first considering the uncertainty of new energy output and the volatility of electricity market prices, a multi time scale revenue model is constructed for day-ahead, intraday, and real-time markets. Then, the objective function is built by maximizing the comprehensive market revenues and is simplified using the synergistic effect of NESs and ESSs. Next, the simplified objective function is solved by the ADMM, and the revenues are maximized while each energy meets the relevant constraints. Lastly, the 33-node network topology is used to illustrate the feasibility of the proposed method. The simulation results show that after optimization, the output of NESs and ESSs can coordinate work in day-ahead, intraday, and real-time markets, while the abandonment power of wind and light is significantly improved.

Impact of State of Health (SOH) on the Thermal Safety of Lithium Ion Cells for Long 1st Life and 2nd Life Applications

Lithium ion battery (LIB) safety incidents can be a threat for people and the environment. Since today, only safety tests on fresh cells are decisive for safety level determination, the effect of long-term operation on their safety characteristics needs to be addressed. A large loss of lithium over long periods of time could, for example, result in reduced structural and thermal stability of the cathode. LIBs are normally used until they reach an end-of-life criterion of typically 70%–80% state of health (SOH). However, they can be reused in second-life applications such as stationary (“grid”) energy storage, afterwards. To ensure safety during long first life and second-life, in this study the influence of aging was investigated over a higher cycle number and a longer time period than ever before. 5 Ah LiNi0.6Co0.2Mn0.2O2(NMC622)||graphite (G) pouch cells were aged at 20 °C between 530 and 3,806 cycles (151–615 d of continuous cycling). SOHs between 91% and 63% were obtained. After aging, the thermal properties of the cells were investigated by heat-wait-search experiments under adiabatic conditions using an accelerating rate calorimeter. The cells showed almost exclusively improvements in their safety characteristics, the thermal runaway even tended to be shifted to higher temperatures.

Medium-Duty Delivery Truck Integrated Bidirectional Wireless Power Transfer System With Grid and Stationary Energy Storage System Connectivity

Medium-Duty Delivery Truck Integrated Bidirectional Wireless Power Transfer System With Grid and Stationary Energy Storage System Connectivity

Diffusive solubility of nitrogen in Propane: Measurement from 96 K to 227 K at 0.1 MPa

The burgeoning demand for large-scale energy storage has catalyzed the advancement of Liquid Air Energy Storage (LAES) technology. However, the liquid-phase propane cold storage process in LAES systems encounters a significant challenge: the dissolution of nitrogen protection gas in propane poses a substantial risk to both operational safety and performance. Given the dearth of data on the diffusive solubility of nitrogen in propane under constant atmospheric pressure and low-temperature conditions, this study constructed a testbench and conducted experiments within a temperature range of 96–227 K at a pressure of 0.1 MPa. The molar diffusive solubilities at 227 K, 176 K, 139 K, and 96 K are 0.030 %, 0.177 %, 0.297 %, and 0.962 %, respectively. Besides, this study also fits a calculation equation for the diffusive solubility of nitrogen in propane, which applies to the propane cold storage process in LAES systems.

Large-scale energy storage for carbon neutrality: thermal energy storage for electrical vehicles

AbstractThermal Energy Storage (TES) systems are pivotal in advancing net-zero energy transitions, particularly in the energy sector, which is a major contributor to climate change due to carbon emissions. In electrical vehicles (EVs), TES systems enhance battery performance and regulate cabin temperatures, thus improving energy efficiency and extending vehicle range. The enhanced efficiency reduces overall energy consumption in EVs. Consequently, this reduction in energy demand can lead to decreased infrastructure needs, minimising the scale and investment required in energy production and distribution systems. Furthermore, the integration of TES with existing infrastructure allows for the simultaneous charging of thermal and electrical energy, leveraging waste heat or renewable energy sources. This not only cuts costs by optimizing resource use but also bolsters sustainability by minimising reliance on non-renewable energy sources. The widespread adoption of TES in EVs could transform these vehicles into nodes within large-scale, distributed energy storage systems, thus supporting smart grid operations and enhancing energy security. Strategic investments and regulatory updates are essential to realise a sustainable, carbon-neutral transportation future, underpinned by robust, cost-efficient infrastructure.

Vanadium-Based Cathodes for Aqueous Zinc-Ion Batteries: Mechanisms, Challenges, and Strategies.

ConspectusZinc-ion batteries (ZIBs) are highly promising for large-scale energy storage because of their safety, high energy/power density, low cost, and eco-friendliness. Vanadium-based compounds are attractive cathodes because of their versatile structures and multielectron redox processes (+5 to +3), leading to high capacity. Layered structures or 3-dimensional open tunnel frameworks allow easy movement of zinc-ions without breaking the structure apart, offering superior rate-performance. However, challenges such as dissolution and phase transformation hinder the long-term stability of vanadium-based cathodes in ZIBs. Although significant research has been dedicated to understanding the mechanisms and developing high-performance vanadium-based cathodes, uncertainties still exist regarding the critical mechanisms of energy storage and dissolution, the actual active phase and the specific optimization strategy. For example, it is unclear whether materials such as α-V2O5, VO2, and V2O3 serve as the active phase or undergo phase transformations during cycling. Additionally, the root cause of V-dissolution and the role of byproducts such as Zn3(OH)2V2O7·2H2O in ZIBs are debated.In this account, we aim to outline a clear and comprehensive roadmap for V-based cathodes in ZIBs. On the basis of our studies, we analyzed intrinsic crystal structures and their correlation with performance to guide the design of V-based materials with high-capacity and high-stability for ZIBs. Then, we revealed the underlying mechanisms of energy storage and instability, enabling more effective design and optimization of V-based cathodes. After identifying the key challenges, we proposed effective design principles to achieve high cycling performance of V-based cathodes and outlined future development directions toward their practical application. Vanadium-based compounds include [VO4] tetrahedrons, [VO5] square pyramids, and [VO6] octahedra, which are connected through a cocorner, coedge and coplane. The [VO4] tetrahedron is inactive, and the [VO5] square pyramid is unstable in aqueous solutions because water attacks the exposed vanadium, whereas stable [VO6] octahedra are desirable because of their ability to reduce from +5 to +3 with minimal structural distortion. Therefore, high-performance vanadium-based oxides in ZIBs should maintain intact [VO6] octahedra while avoiding [VO4] tetrahedra or [VO5] square pyramids. The energy storage mechanism involves H2O/H+/Zn2+ coinsertion. The existence of interlayer water in V-based cathodes significantly improves the rate and cycling performance by expanding galleries, screening Zn2+ electrostatically via solvation, reducing ion diffusion energy barriers, and increasing layer flexibility. The insertion of H+/Zn2+ and the instability of V-based cathodes lead to the formation of byproducts such as basic zinc salts (i.e., Zn4SO4(OH)6·nH2O) and dead vanadium (Zn3(OH)2V2O7·2H2O), whose reversibility strongly affects long-term stability. To increase the cycling stability of vanadium-based cathodes, strategies such as electrolyte modulation and coating have been proposed to decrease water attack on the surface of V-oxides, thereby affecting the formation of byproducts. Additionally, in situ electrochemical transformation, ion preintercalation, and ion exchange were explored to prepare intrinsically stable V-based cathodes with enhanced performance. Furthermore, future research should focus on revealing atomic-scale mechanisms through advanced in situ characterization and theoretical calculations, enhancing rate-performance by facilitating ion/electron diffusion, promoting cycling stability by developing highly stable cathodes and refining interface engineering, and scaling up vanadium-based cathodes for practical ZIB applications.

Stabilizing water and regulating interfacial electrostatic interaction with economical supporting salt for stable Zn metal anode

Developing rechargeable aqueous Zn batteries for large-scale energy storage is impeded by inadequate reversibility and stability of the Zn anode, primarily caused by parasitic reactions and heterogeneous deposition. This study proposes an economical electrolyte strategy to address these Zn-related issues. The addition of a supporting salt enhances the thermodynamic stability of water, reduces the number of highly reactive water molecules, and modulates the interfacial electrostatic interaction. This approach effectively suppresses hydrogen evolution reaction and uncontrolled deposition. Remarkably, the rationally proportioned electrolyte allows a high average Coulombic efficiency of 99.93% for 1000 cycles in a Zn||Cu battery and a prolonged lifespan exceeding 4800 h in Zn||Zn cells. The knock-on effect is that Zn||MnO2 pouch cells deliver stable cycling performance, demonstrating the viability of this approach for practical applications.

Re-understanding and mitigating hydrogen release chemistry toward reversible aqueous zinc metal batteries

Interfacial H2 release severely limits the reversibility and feasibility of aqueous Zn metal batteries for large-scale energy storage. Different from the conventional perception that H2 release mainly originates from the competition between hydrogen evolution reaction and Zn plating process, we herein surprisingly find that non-negligible H2 is also generated during stripping due to the accelerated chemical corrosion of the newly exposed Zn surface. To address this issue, we systematically screened the organic additives with different molecular structures and functional groups. Interestingly, a positive correlation between the adsorption strength of additives and the ability to inhibit the interfacial hydrogen release is found. Taking cysteamine (MEA) as a model additive, a gradient solid electrolyte interphase (SEI) is in situ formed at the Zn surface, acting as a chemical “barrier” to isolate interfacial water molecules from electrode surface consequently enable a higher Coulombic efficiency (>99.5%, 4000 cycles) compared with that of MEA-free electrolyte (98.1%, 189 cycles). This work provides a new understanding of the interfacial hydrogen release mechanism and the criteria for selecting additives for aqueous Zn metal anodes.

Enhanced electrochemical performance of K0.67[Ni0.3Mn0.6Co0.1] O2 as a cathode material for secondary K-Ion batteries: Improved K-Ion insertion and reduced charge transfer barrier

Potassium-ion batteries, with their high operating voltage and cost-efficiency, emerged as promising contenders for large-scale energy storage system. Nevertheless, the practical application is hindered by the significant challenges of achieving high capacity and good rate capability in cathodes. Herein, a novel layered oxide cathode, K0.67[Ni0.3Mn0.6Co0.1] O2 (KNMCO), has been synthesized via solid-state (S-KNMCO) and co-precipitation (C-KNMCO) routes. The X-Ray diffraction (XRD) peaks of KNMCO are identified in R3 m space group and well-indexed to hexagonal unit cell. The FE-SEM shows non-spherical morphologies for both samples. Additionally, high-resolution transmission electron microscopy (HR-TEM) images of the synthesized cathode materials shows the interlayer spacing of S-KNMCO is higher than that of C-KNMCO. Furthermore, the electrochemical performance of S-KNMCO and C-KNMCO is characterized using K-metal as anode and electrolyte KPF6 in EC/DEC (1:1, v/v). The S-KNMCO and C-KNMCO exhibit the maximum specific discharge capacity of ∼101 mAhg-1 and ∼66 mAhg-1 at the current rate of C/20 respectively. Additionally, these cells show the good rate capability and coulombic efficiency (∼94%). This research offers novel perspectives on the development of cathode substances for KIBs.

Electrical Conductivity of Binary, Ternary, Quaternary and Quinary Molten Salt Mixtures Based on NaCl-CaCl2

As intermittent energy sources like solar energy and wind power emerge, the need for energy storage becomes important, energy availability needs to be ensured also when the Sun is not shining, and the wind is not blowing. Energy storage can also be used for peak shaving purposes during periods of high demand. Energy storage solutions need to be inexpensive and reliable. Novel all-liquid batteries are considered one option for stationary energy storage and the Na-Zn battery is currently being investigated. During charging Na metal is formed on the negative electrode from a NaCl containing electrolyte and ZnCl2 is formed from a Zn pool on the positive electrode. The electrical conductivity of the molten salt is an important factor in the ohmic loss through the electrolyte. The composition of the electrolyte decides the electrical conductivity, and this conductivity also changes during the charge/discharge cycles of the battery as the electrolyte composition changes accordingly. Electrical conductivity has been measured on different compositions of NaCl-CaCl2, NaCl-CaCl2-LiCl, NaCl-CaCl2-BaCl2, NaCl-CaCl2-ZnCl2, NaCl-CaCl2-BaCl2-SrCl2, NaCl-CaCl2-BaCl2-ZnCl2 and NaCl-CaCl2-BaCl2-SrCl2-ZnCl2 molten salts in an in-house built apparatus. The smaller ions (Li and Na) give higher electrical conductivity, while the larger ions (Ba, Sr, and Zn) reduce the electrical conductivity.

Scalable production and performance optimization of Na3V2(PO4)3 cathode materials for sodium-ion batteries

The Na3V2(PO4)3 (NVP) cathode materials have garnered significant attention for grid energy storage due to their high theoretical capacity, rate performance, and cyclic stability. However, challenges persist, including inadequate electronic and ionic conductivity. This study addresses these issues through a novel solution-spray drying process using soluble precursors to achieve homogeneous mixing at the atomic level. This method not only promotes the formation of pure-phase NVP but also reduces carbon content effectively. Optimized heat treatment further enhances specific capacity, achieving 114 mAh/g at 0.1C with a coulombic efficiency of 99 %. These results highlight a scalable approach to improve the commercial viability of sodium-ion batteries by enabling efficient production of high-performance NVP cathode composites.

Analysis of the inhibition effects of C6F12O and low-pressure carbon dioxide on 72 Ah LiFePO4 module under the overcharging abuse condition

Fire disasters that happened in the energy storage station of LiFePO4 (LFP) cells have been growing rapidly in recent years. To meet the urgent need for fire and explosion prevention caused by the abused LFP cells, the application of C6F12O and low-pressure carbon dioxide (LCD) is proposed. The inhibition effects are investigated quasi-quantitatively. While the average mass flow rate of LCD is 4 times higher than that of C6F12O, the economy of LCD far exceeds C6F12O (the quality unit price of C6F12O is about 10 times to LCD). In particular, the suppression time of LCD is 9 times shorter than C6F12O when they were all released at the side of the module box alone. LCD shows extraordinary module cooling ability on the overcharged LFP module. The pure C6F12O application makes it hard to prevent thermal runaway over long durations. The releasing position of C6F12O (directly above the safety valve and on the side of the LFP module) is also tested. It is easier to suppress the flame when C6F12O is released directly above the safety valve. Additionally, the re-ignition is observed due to the electrostatic spark generated by the charging wire during the suppression process.

Improving grid reliability with grid-scale Battery Energy Storage Systems (BESS)

The modern electric power system is stable because generation and demand are balanced in real-time. To provide grid managers the leeway to maintain this balance, grid-scale energy storage devices are seeing increased deployment. Another existing technique to achieve a stable and reliable power system today is integrating renewable energies with a battery energy storage system (BESS). Integrating grid-scale BESS to improve grid dependability is crucial since renewable energy sources, which may be somewhat unpredictable, are increasingly being integrated into existing power networks. With its massive electrical energy storage and distribution capabilities, BESS contributes to the grid's ability to balance supply and demand. The BESS helps maintain grid stability by storing energy that is not used during peak hours. This energy comes mostly from renewable sources like solar and wind and is then sent back to the system when the demand is highest. Primary function of BESS includes energy storage and time-shifting, regulation of frequency, voltage support, and enhancement of grid reliability. Development in battery technologies and controls has made them cheaper and inevitable for future power networks. The functions and elements of BESS, the types of electrochemical batteries, the implications of their degradation, and their applications for grid optimization and reliability are discussed in this research. In conclusion, BESS is a significant enabler of grid modernization, resilience, and the evolution of the energy system.

Strategic investments in mobile and stationary energy storage for low-carbon power systems

The main feature and trend of the distribution system is the integration of renewable energy with high penetration rates. The variability and zero marginal cost characteristics of renewable energy will lead to drastically fluctuating locational marginal prices. In the deregulated electricity market, merchants have incentives to utilize energy storage and price arbitrage. Mobile energy storage has a short capital payback period and is widely recognized for transferring energy in the temporal and spatial dimensions. This paper analyses the interaction between merchants and distribution system operators and presents a hybrid energy storage strategic investment framework using bi-level programming. In the upper-level problem, the merchant formulates the capacity, location, and operation strategy of different energy storage to maximize the market revenue of hybrid energy storage, which is paid for by the locational marginal price. In the lower-level problem, the distribution system operator develops an optimal dispatch strategy considering renewable energy and merchant investments. A joint energy and reserve market clearing procedure is performed to derive the locational marginal prices. In the lower-level problem, a data-driven solution strategy based on machine learning is introduced. It uses deep neural networks to approximate the mapping relationship between distribution system states and locational marginal prices. The presented methodology is implemented in an IEEE-33 node system. The results demonstrate that, compared to the basic case, the hybrid energy storage investment strategy has led to an 8.1 % increase in merchant profits and a 12.9 % reduction in the operational costs of the distribution network. The deep neural network approximator fully avoids the lower-level problem with less than 5 % optimality loss.