Storage Materials Research Articles

Biomass-derived materials for energy storage and electrocatalysis: recent advances and future perspectives

AbstractOver the last decade, there has been significant effort dedicated to both fundamental research and practical applications of biomass-derived materials, including electrocatalytic energy conversion and various functional energy storage devices. Beyond their sustainability, eco-friendliness, structural diversity, and biodegradability, biomass-derived materials provide additional benefits, including naturally organized hierarchical structures, rich surface properties, and an abundance of heteroatoms. These characteristics make them appealing candidates for effective energy storage and electrocatalytic energy conversion applications. This review explores the recent advancements in biomass-derived materials for energy storage system (ESS), including supercapacitors and electrocatalytic reactions. We also address the scientific and technical hurdles associated with these materials and outline potential avenues for future research on biomass-based energy conversion applications. By emphasizing the significance of controllable structural designs and modifications, we highlight their crucial roles in advancing this field. Graphical Abstract

Polymeric Materials in Energy Conversion and Storage

Energy conversion and storage devices based on polymeric materials are emerging as a promising avenue for renewable power sources [...]

Progress and Perspective of High‐Entropy Strategy Applied in Layered Transition Metal Oxide Cathode Materials for High‐Energy and Long Cycle Life Sodium‐Ion Batteries

AbstractLayered transition metal oxide (LTMO) cathode materials of sodium‐ion batteries (SIBs) have shown great potential in large‐scale energy storage applications owing to their distinctive periodic layered structure and 2D ion diffusion channels. However, several challenges have hindered their widespread application, including phase transition complexities, interface instability, and susceptibility to air exposure. Fortunately, an impactful solution has emerged in the form of a high‐entropy doping strategy employed in energy storage research. Through the implementation of high‐entropy doping, LTMOs can overcome the aforementioned limitations, thereby elevating LTMO materials to a highly competitive and attractive option for next‐generation cathodes of SIBs. Thus, a comprehensive overview of the origins, definition, and characteristics of high‐entropy doping is provided. Additionally, the challenges associated with LTMOs in SIBs are explored, and discussed various modification methods to address these challenges. This review places significant emphasis on conducting a thorough analysis of the research advancements about high‐entropy LTMOs utilized in SIBs. Furthermore, a meticulous assessment of the future development trajectory is undertaken, heralding valuable research insights for the design and synthesis of advanced energy storage materials.

A Case Study of an Energy Barrier in Li-Ion Battery Cathode Material Using DFT and Post-HF Approaches.

With the ever-increasing interest toward energy storage materials, an accurate understanding of the underlying physicochemical processes becomes mandatory for enabling accurate and predictive simulations. In this study, we apply multilevel quantum chemical calculations on a benchmark material commonly adopted as a cathode in Lithium batteries, Li0.5Co0.5+3Ni0.5+4O2. We estimate the Lithium hopping barrier, a key quantity for the estimate of Li diffusion coefficient, at different levels: Hartree-Fock (HF), density functional theory (DFT), periodic local Møller-Plesset perturbation theory of second order, complemented with a coupled cluster correction evaluated using an embedded-fragment approach. The post-HF methods were used here not only for benchmarking the key quantities themselves but also for assessing the accuracy of different functionals and probing the influence of the long-range and static correlation. For the given system and quantity in question, we observe that obtained results do not significantly vary across different DFT functionals or post-HF methods, which is rather uncommon. Such an agreement between the employed methods suggests that static correlation, even if prominent in this system, cancels out in the studied energy differences. In fact, the values of the T1 diagnostics, which test the reliability of the single-reference description, do vary from one fragment to another. But for certain fragments they are fairly small and of similar magnitude, indicating the applicability of such fragments for the correction. Our best estimate of the reaction barrier is about 0.85 eV.

The Role of Hydrogen in Achieving Sustainable Energy Systems: Challenges and Opportunities

Hydrogen has emerged as a crucial element in the pursuit of sustainable energy solutions due to its versatility and its ability to combust without emitting greenhouse gases. This research examines hydrogen's multifaceted role as an energy carrier, emphasizing its methods of production, storage, and utilization. Recent technological advancements, such as enhanced electrolysis efficiency and innovative storage materials, are explored to tackle existing challenges such as high production costs and energy inefficiencies. Case studies in transportation, industrial applications, and power generation illustrate hydrogen's potential to significantly reduce carbon emissions, supporting global decarbonization endeavors. Strategic investments and supportive policies are identified as an essential to fully capitalize on hydrogen's capabilities, emphasizing the necessity for ongoing innovation and cross-sector collaboration to achieve a sustainable, decarbonized energy future. With the increasing attention of the whole society to climate change, hydrogen energy will play an increasingly important role in creating a green and low-carbon world.

Experimental analysis of a solar air heater using waste mild steel chips as a sensible heat storage material.

Heat storage materials improve the utility of solar air heaters (SAHs) after sunset. This study investigates an improved solar air heater (SAH) performance with baffles and waste mild steel chips as sensible heat storage (SHS) materials. Comparative experimental natural convection heat transfer studies were performed with four different improved air heater setups under similar solar radiation conditions. These setups consist of a flat collector plate (I), a baffled plate collector (II), a flat plate collector with SHS (III) and a baffled plate collector with SHS (IV) respectively. Setups I, II, III and IV were obtained by modifying the same air heater enclosure and each experiment was replicated for three similar sunny days. During the periods, the solar radiation varied in the range of 556-934 W/m2. The maximum thermal efficiencies found for setups I, II, III and IV were 18.76%, 22.40%, 27.21% and 28.22% respectively under natural convection. The highest average useful energy rate was produced by setup IV, followed by setups III, II and I. After sunset, setups III and IV were able to deliver warm air for an extended period of 1h, 18min and 1h, 42min, respectively. It was found that setups III and IV had sensible thermal energy storage reserves of 0.38kJ and 0.53kJ, respectively. The storage efficiencies found for setups III and IV were 60.25% and 70.89%, respectively. Among the four setups, setup IV boasts the most economical energy cost at 1.39 ₹/kWh and having the least payback period of 1year 4months. As a result, the employment of baffles and waste mild steel chips as SHS in a flat plate SAH not only presents a method for harvesting waste for efficient heat retention, but it also effectively uses solar energy for beneficial uses.

Deep Eutectic Solvent and Molten Salt-Assisted Construction of Wheat Straw-Derived N/O Co-Doped Porous Carbon for Flexible Zinc-Air Batteries.

As a common biomass resource, wheat straw is gradually being derived as carbon materials for oxygen reduction reaction (ORR) in zinc-air batteries (ZABs). Herein, the wheat straw-derived carbon was prepared by ball milling and pyrolysis using deep eutectic solvent (DES) as the medium, which avoided the cumbersome procedures. The hydrogen bond of DES was utilized to reconstructed into a hydrogen bond network structure between DES and lignin/cellulose/hemicellulose of wheat straw. The hydrogen bond network structure was converted into N/O co-doped porous carbon (N/O-WSPC) with abundant N/O co-doped sites after high-temperature pyrolysis. Meanwhile, KHCO3 was employed to further generate hierarchical pore structures and increase the specific surface area of the N/O-WSPC. The N/O co-doped sites provided intrinsic ORR activity, while the porous structure facilitates the mass transfer effect. Therefore, the N/O-WSPC exhibited a half-wave potential of 0.87 V (vs. RHE) and a limiting current density of 5.98 mA cm-2 for ORR. The N/O-WSPC-based flexible ZAB displayed an energy density of 652.23 Wh kg-1 and a charging-discharging cycle duration for over 19 h. The DES-assisted strategy facilitates the sustainable and efficient application of wheat straw-derived carbon materials in energy storage and conversion devices.

Effect of Confinement on the Structure-Conductivity Relationship in PEO/LiTFSI Electrolytes in 3D Microporous Scaffolds.

Because 3D batteries comprise solid polymer electrolytes (SPEs) confined to porous scaffolds with high surface areas, the interplay between polymer confinement and interfacial interactions on SPE total ionic conductivity must be understood. This paper investigates contributions to the structure-conductivity relationship in poly(ethylene oxide) (PEO)-lithium bis(trifluorosulfonylimide) (LiTFSI) complexes confined to microporous nickel scaffolds. For bulk and confined conditions, PEO crystallinity decreases as the salt concentration (Li+:EO (r) = 0.0125, 0.0167, 0.025, 0.05) increases. For pure PEO and all r values except 0.05, PEO crystallinity under confinement is lower than in the bulk, whereas the glass transition temperature remains statistically invariant. At 298 K (semicrystalline), total ionic conductivity under confinement is higher than in the bulk at r = 0.0167 but remains invariant at r = 0.05; however, at 350 K (amorphous), total ionic conductivity in confinement is lower than in the bulk for both salt concentrations. Time-of-flight secondary ion mass spectrometry indicates selective migration of ions toward the polymer-scaffold interface. In summary, for the 3D structure studied, polymer crystallinity, interfacial segregation, and tortuosity play important roles in determining total ionic conductivity and, ultimately, the emergence of 3D SPEs as energy storage materials.

Bacterial Cellulose Applications in Electrochemical Energy Storage Devices.

Bacterial cellulose (BC) is produced via the fermentation of various microorganisms. It has an interconnected 3D porous network structure, strong water-locking ability, high mechanical strength, chemical stability, anti-shrinkage properties, renewability, biodegradability, and a low cost. BC-based materials and their derivatives have been utilized to fabricate advanced functional materials for electrochemical energy storage devices and flexible electronics. This review summarizes recent progress in the development of BC-related functional materials for electrochemical energy storage devices. The origin, components, and microstructure of BC are discussed, followed by the advantages of using BC in energy storage applications. Then, BC-related material design strategies in terms of solid electrolytes, binders, and separators, as well as BC-derived carbon nanofibers for electroactive materials are discussed. Finally, a short conclusion and outlook regarding current challenges and future research opportunities related to BC-based advanced functional materials for next-generation energy storage devices suggestions are proposed.

The Fabrication of ZIF-L Derived Zns/Mos2@NC Anode Materials for Remarkable Lithium-Ion Storage.

The enhancement of electrochemical performance in lithium-ion batteries can be achieved through the incorporation of MoS2 with carbon materials and various metal sulfides. In this study, a ZnS/MoS2 heterostructure was developed, featuring a two-dimensional nitrogen-doped carbon nanosheet (NC) backbone. The synthesis of ZnMoZIF-L precursors was accomplished by introducing a Mo source in a 1 : 1 molar ratio during the ZIF-L synthesis process. Following high-temperature carbonization and vulcanization treatment, ZnS/MoS2@NC composite materials were successfully synthesized. Compared to the unvulcanized ZnO/MoO3@NC and MoS2 samples, the ZnS/MoS2@NC composite exhibits remarkable lithium storage performance. At a current density of 500 mA g-1, the initial reversible capacity capacity is still as high as 1674 mAh g-1. Furthermore, this composite material demonstrates optimal rate capabilities and a significant contribution to pseudocapacitance. The nitrogen-doped carbon framework effectively mitigates volume changes, while the heterostructural design provides more active sites for lithium-ions, thereby enhancing lithium storage performance.

Transition Metal-Doped Layered Iron Vanadate (FeV3-xMxO9.2.6H2O, M = Co, Mn, Ni, and Zn) for Enhanced Energy Storage Properties

With its distinctive multiple electrochemical reaction, iron vanadate (FeV3O9.2.6H2O) is considered as a promising electrode material for energy storage. However, it has a relatively low practical specific capacitance. Therefore, using the low temperature sol–gel synthesis process, transition metal doping was used to enhance the electrochemical performance of layered structured FeV3O9.2.6H2O (FVO). According to this study, FVO doped with transition metals with larger interlayer spacing exhibited superior electrochemical performance than undoped FVO. The Mn-doped FVO electrode showed the highest specific capacitance and retention of 143 Fg−1 and 87%, respectively, while the undoped FVO showed 78 Fg−1 and 54%.

The extraction of inorganic phase-change materials from sugar industry wastes with the purpose of solid waste management

ABSTRACT This study focused on the feasibility of identifying and recycling inorganic phase-change materials (PCMs) from sugar industry wastes in two cities of Qazvin and Hamadan in Iran. In this study, dry sugar beet pomace, sugar beet pomace, sugar beet molasses, leaves and plant residues of sugar beet and sugarcane bagasse were investigated. The inorganic materials were identified by X-ray Diffraction (XRD), thermal characteristics were determined by differential scanning calorimetry (DSC), and morphological characteristics were determined by scanning electron microscopy (SEM). Additionally, physical and thermal properties of molasses and bagasse samples were analyzed to determine their suitability as inorganic PCMs. The results of this study demonstrated that molasses and bagasse have the potential to be used as mineral PCMs in thermal energy storage applications. The results of this study demonstrated that in the wet sugar beet pomace the highest and lowest concentrations of inorganic PCMs were silicon dioxide (SiO2) and sodium chloride (NaCl), respectively. Moreover, the highest calcium fluoride (CaF₂) composition was reported in dry sugar beet pomace. In the samples of leaves and residues of sugar beet and sugarcane bagasse, the highest concentration of was NaCl. The detection and recycling of mineral PCMs from sugar industry wastes offer a sustainable solution for waste management and provide a renewable source of thermal energy storage materials. Implication Statement This study demonstrated the potential for the extraction of inorganic phase-change materials from sugar industry wastes as a means of solid waste management. By repurposing these materials, we can reduce the environmental impact of sugar production and contribute to sustainable practices in the industry.

Self-limited and reversible surface hydration of Na2Fe(SO4)2 cathodes for long-cycle-life Na-ion batteries

Air stability is a crucial factor in the practical application of a battery material, as it profoundly affects the material's preparation, storage, and electrode fabrication processes. Sodium iron sulfate cathodes, despite their attractive attributes in cost and electrochemical performance, are widely believed to be unstable upon air exposure because of the sulfate group. Here we report remarkable air-stability of the Na2Fe(SO4)2-based (NFS) cathodes (minimal decay in 20 % RH air for 60 days, 91.9 % capacity retention after 3500 cycles in half cells) and their outstanding cycle performance in practically relevant pouch-type full cells (∼100 Wh kg-1 specific energy, >1000 cycle-life). Although the NFS cathodes do react with moisture H2O to produce Na2Fe(SO4)2⋅4H2O but the hydration is spatially confined at the NFS particles’ surface and not propagating into their bulk. Further, the structural changes are reversible when the surface-hydrated NFS particles are heated in the typical electrode vacuum-drying process, avoiding extra treatment and additional cost. This work reveals the promising properties of the NFS cathode materials towards high-performance and sustainable Na-ion batteries.

A Dual Effect Additive Modified Electrolyte Strategy to Improve the Electrochemical Performance of Zinc-Based Prussian Blue Analogs Energy Storage Device.

Prussian blue analogs (PBA) exhibit excellent potential for energy storage due to their unique three-dimensional open framework and abundant redox active sites. However, the dissolution of transition metal ions in water can compromise the structural integrity of PBAs, leading to significant issues such as low cycle life and capacity decay. To address these challenges, we proposed a dual-effect additive-modified electrolyte method to alleviate such issues, introducing sodium ferrocyanide (Na4Fe(CN)6) into aqueous alkaline electrolytes. It could not only capture Zn2+ dissolved on the surface of Na1.86Zn1.46[Fe(CN)6]0.87 (ZnHCF) electrode material during the cycling process but also conduct redox reactions on the electrode surface to provide additional capacitance. Through experiments and molecular simulation calculations, it showed that Na4Fe(CN)6 can restrict the movement of Zn dissolution into the electrolyte on the electrode surface. Based on this, an asymmetric supercapacitor based on ZnHCF//activated carbon was assembled with a modified electrolyte. The assembled supercapacitor displayed a specific capacitance of 1,329.65 mF cm-2, a power density of 2,900 mW cm-2, and an energy density of 388.28 mW h cm-2. This study provides a new idea for the design and construction of stable and efficient PBA energy storage materials by inhibiting the leaching of transition metals in PBA.

Enhancing electrode efficiency by tuning surface electronic properties and defects in NiFe layered double hydroxide nanosheets with Al or Zn cation vacancies

Layered double hydroxides (LDHs) containing transition metals have emerged as promising electrode materials for supercapacitors due to their low cost, strong redox activity, and environmental friendliness. In this study, we propose a novel approach by creating Zn-defect Zn(II) engineered D-NiFeZn-LDHs through cyclic voltammetry etching in an alkaline solution of NiFeZn-LDHs synthesized on a carbon cloth substrate. This defect engineering increases electrochemical active sites and improves ion diffusion within the layered structure. The D-NiFeZn-LDHs demonstrate an impressive specific capacitance of 1204.8 F g⁻1 at 1 A g⁻1 and retain 61.52 % of their initial capacity after 10,000 cycles at 10A g⁻1, showcasing excellent long-term cycling stability. Moreover, the all-solid-state asymmetric supercapacitor constructed using D-NiFeZn-LDHs delivers a high energy density of 31.63 Wh kg⁻1 at 125 W kg⁻1 and retains 65.95 % of its capacity after 5000 cycles at a high current density of 10 A g⁻1. These findings provide a new strategy for developing high-performance energy storage materials.

Zinc hexacyanoferrate with open framework for efficient aqueous cobalt ions storage

In this work, we report a high-performance aqueous Co-ion battery with zinc hexacyanoferrate as Co2+ storage material. Owing to the open framework, zinc hexacyanoferrate exhibits excellent electrochemical performance. The reversible capacity of zinc hexacyanoferrate is up to 62.4 mAh g−1 at 5C with ultralow capacity decay (0.0084 % per cycle) within 500 cycles. Even cycled at a higher rate of 10C, zinc hexacyanoferrate still can remain a high capacity retention of 98.8 % after 700 cycles. The excellent electrochemical performance is attributed to the rapid kinetics behavior of Co2+ in the open and stable framework structure. Besides, a joint analysis of in-situ X-ray diffraction, ex-situ Fourier transform infrared spectroscopy and ex-situ X-ray photoelectron spectroscopy verifies the highly reversible structural change of zinc hexacyanoferrate during charge/discharge process. All these evidences suggest that zinc hexacyanoferrate may be a promising host material for Co2+ storage in aqueous rechargeable batteries.

Performance evaluation of nano-enhanced phase change materials for thermal energy storage: An experimental study

In rapidly developing economies, the increasing energy demand and fossil fuel consumption have made the need for renewable energy sources and efficient thermal energy storage (TES) solutions more urgent than ever. This study focuses on enhancing the thermal energy storage capabilities of paraffin-based phase change materials (PCMs) by incorporating Al2O3, MgO, and CuO nanoparticles. The evaluation of nano-enhanced PCMs focused on their melting temperatures, thermal storage capacities, thermal conductivities, and charge/discharge times. The experimental results revealed significant changes in the thermal properties of the nano-enhanced PCMs compared to pure paraffin. The melting temperature was raised by 2 °C due to Al2O3 nanoparticles, whereas CuO and MgO nanoparticles decreased it by 1.7 °C and 1.8 °C, respectively. Compared to pure paraffin, Al2O3-PW, MgO-PW, and CuO-PW exhibited improvements of 13 %, 39 %, and 48 % in thermal conductivities, respectively. CuO-doped paraffin showed an 11.8 % decrease in discharge time, suggesting its suitability for rapid heat transfer applications like defrosting systems or thermal management in electronics. On the other hand, paraffin doped with MgO showed a minimal 2.24 % reduction in discharge time, indicating its effectiveness in applications requiring heat retention, particularly for improved thermal insulation in building materials. The results highlighted the potential of nano-enhanced PCMs in energy storage and construction is underlined, offering a sustainable approach to improving energy efficiency in various sectors.

Ca-decorated holey graphyne for reversible hydrogen storage: Insights from DFT analysis

We theoretically examine the hydrogen storage capabilities of a newly synthesized carbon allotrope known as holey graphyne (HGY). HGY exhibits weak interaction with H2, making it unsuitable for storage, thus prompting surface modification. Ca binds to HGY with a binding energy of −2.03 eV and experiences a diffusion energy barrier of 1.49 eV. The supercell of HGY accommodates six Ca atoms, and each Ca atom binds five H2 with an average binding energy of −0.27 eV, resulting in an uptake capacity of 12.07 wt% and desorption temperature of 331K at 5 bar. AIMD simulation and positive phonon frequencies confirms thermal and dynamic stability of Ca-decorated HGY. RDG analysis reveals electrostatic interactions between Ca and HGY, and van der Waals interactions between H2 and Ca. Thus, Ca-decorated HGY shows exceptional uptake capacity, desirable adsorption energy and desorption temperature, making it a suitable material for on-board reversible hydrogen storage in light vehicles.

High-performance α-Fe2O3 nano cubes as anode for supercapacitors

Abundant availability, high theoretical specific capacitance and low cost of transition metal oxides such as iron oxides, make them attractive as electrode materials for energy storage. In order to achieve improved performance, high conductivity, shorter ion-diffusion path, and faster ion accessibility, rational design of morphology of electrode material is highly desirable. We have successfully synthesized mesoporous α-Fe2O3 nanocubes to achieve high specific capacitance and better retention. The as-prepared and annealed α-Fe2O3 nanocubes show high reversible redox activity along with good thermodynamic stability. These nanostructure give rise to high specific capacitance and ~90 % of the capacitance can be retained even after 1000 redox cycles, suggesting good cyclic stability. The electrochemical performance of mesoporous α-Fe2O3 nanocubes is attributed to the morphological features, which results in efficient K+ ion transport into the pores. A two electrode α-Fe2O3//NiO device is fabricated, which shows excellent power and energy density of ∼627 W/kg and ∼23.32 Wh/kg, respectively. Our work demonstrates that 3D nanoporous α-Fe2O3 electrodes forms promising material system as anode for improved charge storage performance.

Nanocellulose/metal-organic frameworks composites for advanced energy storage of electrodes and separators

Nanocellulose is widely utilized in various fields due to its high surface area, excellent mechanical strength, and environmental friendliness. However, nanocellulose is an insulating material with typically low electrical conductivity. Metal-organic frameworks (MOFs) are appealing because of their huge specific surface areas, highly flexible pore size and porosity, diverse topological structure, changeable surface chemistry, and good chemical and thermal strength. The high porosity and surface area, good electrical conductivity, excellent mechanical strength, and flexibility of nanocellulose/MOF composites (NC/MOFs) make it a promising material for energy storage. This paper provides a review of the synthesis and application of NC/MOFs for energy storage of electrodes and separators. It presents the physical and chemical properties of nanocellulose and MOF. Particularly, two preparation strategies for NC/MOFs, the in-situ synthesis method and the ex-situ blending method, are introduced. Then the applications of NC/MOFs in energy storage of electrodes and separators are delivered, including supercapacitors, lithium-ion batteries, sodium-ion batteries, and others. Finally, the challenges and prospects of NC/MOFs for energy storage are addressed.