Potential Energy Storage Research Articles

Template‐Induced Graphitic Nanodomains in Nitrogen‐Doped Carbons Enable High‐Performance Sodium‐Ion Capacitors

Sodium‐ion capacitors (SICs) have great potential in energy storage due to their low cost, the abundance of Na, and the potential to deliver high energy and power simultaneously. This article demonstrates a template‐assisted method to induce graphitic nanodomains and micro‐mesopores into nitrogen‐doped carbons. This study elucidates that these graphitic nanodomains are beneficial for Na+ storage. The obtained N‐doped carbon (As8Mg) electrode achieved a reversible capacity of 254 mA h g−1 at 0.1 A g−1. Moreover, the As8Mg‐based SIC device achieves high combinations of power/energy densities (53 W kg−1 at 224 Wh kg−1 and 10 410 W kg−1 at 51 Wh kg−1) with outstanding cycle stability (99.7% retention over 600 cycles at 0.2 A g−1). Our findings provide insights into optimizing carbon's microstructure to boost sodium storage in the pseudocapacitive mode.

ZnO-PANI nanocomposite: Enhanced electrochemical performance towards energy storage

In the present investigation a novel nanocomposite composed of Polyaniline (PANI) and Zinc Oxide (ZnO) has been evaluated for its structural, morphological, and electrochemical properties for its application as high-performance Li-ion battery electrode. The X-ray diffraction (XRD) and Furrier transform infrared (FTIR) spectral analysis confirmed the synthesis of ZnO-PANI nanocomposite. The Field emission- scanning electron microscopy (FE-SEM) images confirmed the uniform distribution of ZnO nanoparticle in PANI matrix, while BET surface area analysis revealed a narrow mesoporous pore distribution with high surface area, enhancing its potential for energy storage. The electrochemical assessment using CR2032 coin cells showcased the remarkable performance of the ZnO-PANI nanocomposite as an electrode material for energy storage. Cyclic voltammetry (CV) analysis revealed distinct reduction and reformation peaks related to ZnO and Li+ insertion into the PANI matrix. The nanocomposite displayed a high specific capacity, with an initial discharge capacity of 1052 mA h g−1, followed by stable performance in subsequent cycles. Notably, Coulombic efficiency consistently exceeded 98 % from the 10th cycle, demonstrating excellent performance. The rate capability was equally impressive, delivering discharge capacities from 1052 mA h g−1 at 0.1C to 771 mA h g−1 at 2C. Long-term cycling tests illustrated exceptional capacity retention, with 92.99 % capacity retained after 500 cycles and outstanding Coulombic efficiency consistently above 99 %. In conclusion, the ZnO-PANI nanocomposite exhibits desirable structural and morphological attributes, exceptional electrochemical performance, and potential for advanced energy applications, particularly in Li-ion batteries.

Influence of metal encapsulation on thermophysical properties and heat transfer in salt hydrate phase change material for air conditioning system

Phase change materials (PCM) are gaining increasing attention as a cold energy storage technology for air conditioning systems due to their potential to reduce electrical grid loading, energy consumption, and electricity costs. However, realizing the full potential of PCM-based cold energy storage in practical applications is constrained by low cold energy transfer efficiency within air conditioning systems. This study addresses this challenge by exploring the encapsulation of salt hydrate PCM using six different metals to enhance heat transfer efficiency. Additionally, the corrosion behaviors of the PCM towards these metals were thoroughly evaluated. Notably, copper demonstrated the highest corrosion rate, and the resulting corrosion products, particularly from copper and brass, were found to substantially reduce the energy storage capacity of PCM. Moreover, PCM encapsulated into aluminum alloy exhibited higher heat transfer efficiency than that of stainless steel. In light of these findings, aluminum alloy is recommended as the optimal choice for PCM encapsulation, given its corrosion resistance and minimal effect on thermal properties. This research provides crucial insights for selecting appropriate metals to enhance the efficiency and durability of air conditioning systems utilizing salt hydrate PCM.

Cobalt/MXene‐derived TiO2 Heterostructure as a Functional Separator Coating to Trap Polysulfide and Accelerate Redox Kinetics for Reliable Lithium‐sulfur Battery

AbstractLithium‐sulfur (Li−S) batteries are one of the most potential new energy storage systems due to their high theoretical capacity (1675 mAh g−1) and high energy density (2600 Wh kg−1). However, the application of Li−S batteries is currently restricted due to the dissolution of polysulfides in the electrolyte, which leads to the shuttle effect of lithium polysulfides (LiPSs). Here, we present a Co@MXene‐derived TiO2 heterostructure decorated on carbon sheets derived from folic acid (Co@M‐TiO2/C) as a functional separator coating to trap polysulfide and accelerate redox kinetics in Li−S batteries. The interconnected porous structure with good electrical conductivity of the heterostructure boasts rapid ion diffusion and efficient electron transfer within the battery. By attaching Co and MXene‐derived dual‐phased TiO2 to two‐dimensional carbon sheets, heterostructures are formed, ensuring complete exposure of the active sites. These heterostructures exhibit catalytic effects on LiPSs and excellent adsorption capabilities, effectively inhibiting the shuttle effect and accelerating the redox kinetics. Considering these advantages, the Li−S battery with the optimized Co@M‐TiO2/C modified separator demonstrates a high specific capacity of 1481.7 mAh g−1 at 0.2 C, superior rate performance of 855.5 mAh g−1 at 2 C, and excellent cycling performance under a high sulfur load of 4.4 mg cm−2.

Effective d–p orbital hybridization of Co0.75Fe0.25P catalysts enabling high-rate and long-life lithium‒sulfur batteries

Lithium–sulfur (Li–S) batteries represent one of the potential next-generation energy storage devices. However, their commercialization is hindered by the severe shuttle effect of lithium polysulfides (LiPSs) and sluggish redox kinetics. A crucial strategy to address these issues involves the rational design of catalysts and a comprehensive understanding of interaction mechanisms between catalysts and sulfur species. In this study, Fe atoms were incorporated into CoP catalysts, and one-dimensional (1D) porous carbon-encapsulated Fe-doped CoP (Co1-xFexP@C) nanotube-like nanostructures were rationally designed and successfully synthesized. This design involves modifying the d–p orbital hybridization between the transition metal Co 3d orbitals and S 2p orbitals through the Fe 3d orbitals, thus creating catalysts with the most effective d–p orbital hybridization and, consequently, the strongest electrocatalytic activity. Detailed kinetic analysis reveals the Co0.75Fe0.25P@C catalyst, with an effective d–p orbital hybridization, can firmly anchor the LiPSs, inhibit the shuttle effect, and facilitate bidirectional Li2S redox, thereby enhancing sulfur utilization and promoting LiPS conversion. These findings enable high-rate and long-cycle-life Li–S batteries. Specifically, the Li–S battery using the Co0.75Fe0.25P@C catalyst demonstrates excellent cycling stability, with a low capacity decay rate of 0.05 % per cycle over 900 cycles at 2 C. More impressively, the Li–S battery also achieves outstanding high-rate performance, delivering 726.3 mAh g–1 at 6 C. This study introduces a new strategy for identifying catalysts with the strongest electrocatalytic activity, which holds promise for advancing the development of Li−S batteries.

NaNbO3‐Based Multilayer Ceramic Capacitors with Ultrahigh Energy Storage Performance

AbstractWith the gradual promotion of new energy technologies, there is a growing demand for capacitors with high energy storage density, high operating temperature, high operating voltage, and good temperature stability. In recent years, researchers have been devoted to improving the energy storage properties of lead‐based, titanium‐based, and iron‐based multilayer ceramic capacitors (MLCCs). However, limited research has been conducted into MLCC development using NaNbO3 (NN)‐based materials. In this paper, the successful achievement of excellent overall energy storage performance in a novel NaNbO3–(Bi0.5Na0.5)TiO3–Bi(Mg0.5Hf0.5)O3 lead‐free MLCCs is presented. The disordered tilting around the cp axis, disrupts Na and Bi ions' long‐range displacements and induces PNRs and strong relaxor behavior, which ensures a superior energy storage performance, together with the multilayer ceramic design strategy. As a result, the NN‐based MLCC device presents an ultra‐high Wrec = 12.65 J cm−3 and η = 88.5%, simultaneously showing superior temperature stability (Wrec varies <±1% and η varies <±6% from −50 to 125 °C) and fatigue resistance (Wrec and η vary <±1% over 107 cycles). This study highlights the advanced energy storage potential of NaNbO3‐based MLCCs for various applications, and ushers in a new era for designing high‐performance lead‐free capacitors that can operate in harsh environments.

One-pot in situ synthesis of expandable graphite-encapsulated paraffin composites for thermal energy storage

To mitigate the intermittency of renewable energy generation and achieve net-zero greenhouse gas emissions, a cyclically stable and energy-efficient thermal energy storage system (TESS) is increasingly required. To prevent leakage and enhance thermal conductivity and stability, TESS is typically fabricated by impregnating energy storage materials (ESMs) into porous conductive additives. However, the impregnation-based encapsulation process is both time-consuming (several to tens of hours) and energy-intensive, and the incorporation of additives reduces the proportion of ESMs, resulting in decreased energy capacity. In this study, we present an ultrafast (several minutes) and energy-efficient one-pot encapsulation method for in situ encapsulation of paraffin wax (PW) within the pores of expanded graphite (EG) via microwave irradiation of expandable graphite (Eg) in molten PW. The resulting binary PW/EG composites exhibit shape stability and no leakage even at 92 wt% PW loading. The PW/EG composite with 10 wt% EG demonstrates a thermal conductivity of 3.7 W/mK (16.2 times higher than that of pure PW), a thermal release/absorption efficiency of around 99.5 %, and almost 100 % capacity retention after thermal cycling. Additionally, we demonstrate that integrating PW/EG TESS with thermoelectric (TE) modules can increase TE power generation by more than fivefold, highlighting their potential for energy storage and conversion as well as mitigating waste heat source intermittency.

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Covalent triazine framework nanosheets (CTF NSs), an emerging class of two‐dimensional polymeric nanomaterials, have received great attention due to their abundant active sites, permanent periodic porosity, molecular structural diversity, superior chemical and thermal stability, and short charge diffusion path, thus demonstrating great potential in energy storage and conversion. More details are discussed in the review article by Xu et al. on page 301—316.image

Chlorination for all solid-state zinc-graphite battery: Investigate into the charge-discharge mechanism of zinc electrodes and sodium silicate electrolyte

Zn solid-state batteries offer a novel and environmentally friendly energy storage solution with excellent safety features. This study explores the material characteristics and electrochemical mechanisms of the Zn anode and sodium silicate solid electrolyte powder after HCl chlorination. Results reveal the formation of Zn chloride hydroxide monohydrate (Zn5OH8Cl2⋅H2O, known as Simonkolleite) in the zinc anode post HCl treatment. The compound's layered structure enhances ion transport. The sodium silicate electrolyte exhibits increased surface area after HCl treatment. In engineering applications, a solid-state battery assembled with Simonkolleite anode, electrolyte (HB), and graphite film (GF) cathode demonstrates a high capacity (>5000 mAh/g) in the first discharging cycle and impressive stability over 30–100 cycles, highlighting its promising potential for energy storage.

A high-performance magnesium/lithium hybrid-ion battery using a hollow multi-layered NiS/Co3S4/carbon cathode and an all-phenyl-complex-based electrolyte.

Magnesium-lithium hybrid batteries (MLHBs) using a dual-ion electrolyte and safe Mg anode have promising potential for high-performance energy storage. Here, we develop an MLHB constructed of a hollow multi-layered NiS/Co3S4/carbon cathode and an all-phenyl-complex/lithium chloride (APC-LiCl) electrolyte. The hollow multi-layered structure and carbon matrix accommodate volumetric expansion and facilitate electrolyte penetration. The APC-LiCl electrolyte displays a stable electrochemical window. The MLHB shows a high specific capacity of 398 mA h g-1 after 100 cycles at 0.2 A g-1, and a stable capacity at 1.0 A g-1 after cycling 500 times. Moreover, stable rate performance and temperature tolerance are achievable. These findings would enable this design to be promising for developing other hybrid battery systems.

Morphology and selectivity of hydrated alkali metal ions as depth of discharge in the 1T-MoS2 electrode with aqueous electrolytes.

Aqueous ion batteries have great commercial potential in green power and energy storage due to their green nature, safety and high ionic conductivities. Different from organic electrolytes, alkali ions (Li+, Na+, and K+) inevitably bring water molecules into the electrodes during the charging/discharging process due to the hydration of ions with water molecules. The selectivity of alkali ions and the mechanism of how water molecules are involved in the ion extraction/insertion process in the electrodes have not been clarified. In this study, we focus on the characteristics of the intra-layer distribution of different hydrated ions (Li+, Na+, and K+) and the quantitative analysis of the selectivity of hydrated cations in aqueous batteries. We found that the concentration of hydrated ions greatly affects their distribution within the 1T-MoS2 layers, and the presence of hydrogen bonding and O-O repulsive forces between water molecules causes the hydrated ions to gradually form chains from the dispersed state under the effect of hydrogen bonding and ionic bonding, then further form strips, and ultimately be densely dispersed within the whole layer. In addition, the chemical potential difference of hydrated ions is the key to the competitive reaction, and we quantitatively analyze the selectivity relationship between hydrated cations throughout the charging and discharging process; hydrated sodium ions will have better performance than lithium and potassium ions in aqueous batteries.

Insights into the capacity fading and failure mechanism of an O3-NaNi1/3Fe1/3Mn1/3O2 layered oxide cathode material for sodium-ion batteries

Low-cost sodium-ion batteries hold great potential for large-scale energy storage owing to the abundance of sodium reserves.

Inducing preferential growth of the Zn (002) plane by using a multifunctional chelator for achieving highly reversible Zn anodes.

Aqueous zinc-ion batteries (AZIBs) have demonstrated great potential for large-scale energy storage. However, their practical applications have been restricted by fast Zn dendrite growth and severe side reactions at the Zn/electrolyte interface. Herein, sodium gluconate is incorporated into a mild acidic electrolyte as a multifunctional additive to stabilize the Zn anode. Experiments and theoretical calculations reveal that the SG additive can induce planar growth of Zn along its (002) direction, thereby inhibiting Zn dendrite growth. This dendrite inhibition effect is attributed to the preferential adsorption of Zn2+ on the Zn (002) plane, while the Zn (100) and (101) planes are shielded by gluconate ions. Consequently, Zn||Zn symmetric cells with the electrolyte additive exhibit significantly prolonged cycle lives of 2000 h at 1 mA cm-2, 1 mA h cm-2 and 900 h at 5 mA cm-2, 2.5 mA h cm-2. Futhermore, the Zn||NH4V4O10 full cell retains 95% of its initial capacity after 2000 cycles at a current density of 5 A g-1 with an average CE of nearly 100%. This work offers a cost-effective strategy to enhance the electrochemical performance of AZIBs.

Facile synthesis of O/N co-doped hierarchical porous carbon: for high performance supercapacitors and electromagnetic interference shielding

Biomass can be used to prepare carbon materials with excellent pore structures and rich surface properties based on its chemical properties, and have great potential in electrochemical energy storage and electromagnetic interference shielding.

Layered CrO2·nH2O as a cathode material for aqueous zinc-ion batteries: ab initio study.

Aqueous zinc-ion batteries are considered potential large-scale energy storage systems due to their low cost, environmentally friendly nature, and high safety. However, the development of high energy density cathode materials and uncertain reaction mechanisms remains a major challenge. In this work, the reaction mechanism, discharge voltage and diffusion properties of layered CrO2 as a cathode material for aqueous zinc-ion batteries were studied using first-principles calculations, and the effect of pre-intercalated structural water on the electrochemical performance of CrO2 electrodes is also discussed. The results show that CrO2 exhibits high average discharge voltages (2.65 V for H insertion (pH = 7) and 1.97 V for Zn insertion) and medium theoretical capacities (319 mA h g-1 (H and Zn)). The H intercalation voltage strongly depends on the pH value of the electrolyte. The H/Zn co-insertion mechanism occurs at low hydrogen concentrations (c(H) ≤ 0.125), where the initial insertion of H reduces the total amount of subsequent Zn insertion. For the substrate containing structured water (CrO2·nH2O, n ≥ 0.5), the average voltage of Zn insertion is significantly increased, while the average voltage of H slightly decreases. In addition, the pre-intercalated water strategy significantly improved the diffusion properties of H and Zn. This study shows that layered CrO2·nH2O is a promising cathode material for aqueous zinc-ion batteries, and also provides theoretical guidance for the development of high-performance cathode materials for aqueous zinc-ion batteries.

Tailoring anisotropic thermal conductivity of 2D aramid nanoribbon-based dielectrics with potential high-temperature capacitive energy storage

Tailoring the high anisotropic thermal conductivity of polymer dielectrics for enhanced high-temperature breakdown strength with potential capacitive energy storage.

Electrochemical and spectroscopic characterisation of organic molecules with high positive redox potentials for energy storage in aqueous flow cells

Electrochemical and spectroscopic characterisation of organic molecules with high positive redox potentials for energy storage in aqueous flow cells

Synergistic design of a semi-hollow core-shell structure and a metal-organic framework-derived Co/Zn selenide coated with MXene for high-performance lithium-sulfur batteries.

Lithium-sulfur batteries have garnered significant interest as potential energy storage systems for the future, owing to their remarkable theoretical specific capacity (1675 mA h g-1) and energy density (2600 W h kg-1). However, their development has been severely impeded by several challenges, including the low intrinsic conductivity of sulfur, volume expansion issues, and the polysulfide shuttle effect. To address these issues, polar metal compounds with nanostructures featuring hollow shells and catalytic functions have emerged as promising materials for designing advanced lithium-sulfur batteries. In this study, bimetallic selenides with varying degrees of hollowness are synthesized using a tannic acid etching and selenization strategy. By comparing the electrochemical characteristics of composite electrodes with different degrees of hollowness, an optimal semi-hollow core-shell structure is identified, implying that reasonable structural designing of metal compounds carries immense importance in improving electrochemical reactions. Moreover, the appropriate degree of hollowness effectively mitigates volume expansion issues associated with the sulfur cathode. Consequently, bimetallic selenides with a hollow core-shell structure coated with conductive MXene material exhibit superior electrochemical performance. The synergistic effect achieved through the judicious design of the hollow core-shell structure and the utilization of polar metal compounds has proved instrumental in enhancing the redox kinetics of lithium-sulfur batteries. As such, this research presents a novel avenue for the development of high-performance lithium-sulfur batteries.

Photoswitchable hydrazones with pyridine-based rotors and halogen substituents.

The Z,E-photoisomerization of pyridine-based hydrazone switches is typically suppressed due to the presence of pyridine-based rotors. The crystal structures of studied compounds were investigated using theoretical methods combining DFT and QT-AIM calculations to unveil the nature and properties of the intramolecular hydrogen bonding. In this study, we introduced a new series of pyridine-based hydrazones anchored with o-halogen substituents (2-X) and investigated their photoswitching abilities using 1H NMR and UV-Vis spectroscopy. The efficiency of the photoisomerization from initial 2-X-Z to the 2-X-E isomer varied, with the highest yield observed for 2-Cl-E (55%). Our findings, supported by DFT calculations, revealed the formation of a new diastereomer, 2-X-E*, upon back-photoisomerization. We demonstrated that hydrazones from the 2-X series can be reversibly photoswitched using irradiation from the UV-Vis range, and additionally, we explored the effect of the halogen atom on their switching capabilities and also on their thermodynamics and kinetics of photoswitching, determining their molecular solar thermal energy storage potential.

Regulation of dual-atom doped porous carbon towards high-performance capacitive storage devices

Zinc ion capacitors show impressive energy storage potential for well-balanced energy and power density, but exploring their implicit energy storage mechanism is crucial and still challenging.