High Energy Density Research Articles

A Large-Scale Fabrication of Flexible, Ultrathin, and Robust Solid Electrolyte for Solid-State Lithium-Sulfur Batteries.

All-solid-state lithium metal batteries (ASSLMBs) are considered as the most promising candidates for the next-generation high-safety batteries. To achieve high energy density in ASSLMBs, it is essential that the solid-state electrolytes (SSEs) are lightweight, thin, and possess superior electrochemical stability. In this study, a feasible and scalable fabrication approach to construct 3D supporting skeleton using an electro-blown spinning technique is proposed. This skeleton not only enhances the mechanical strength but also hinders the migration of Li-salt anions, improving the lithium-ion transference number of the SSE. This provides a homogeneous distribution of Li-ion flux and local current density, promoting uniform Li deposition. As a result, based on the mechanically robust and thin SSEs, the Li symmetric cells show outstanding Li plating/stripping reversibility. Besides, a stableinterfacecontact between SSE and Li anode has been established with the formation of an F-enriched solid electrolyte interface layer. The solid-state Li|sulfurized polyacrylonitrile (Li|SPAN) cell achieves a capacity retention ratio of 94.0% after 350 cycles at 0.5 C. Also, the high-voltage Li|LCO cell shows a capacity retention of 92.4% at 0.5 C after 500 cycles. This fabrication approach for SSEs is applicable for commercially large-scale production and application in high-energy-density and high-safety ASSLMBs.

Two‐Dimensional Layered Hydroxide Materials for Nucleophile Oxidation

AbstractThe global energy crisis highlights the need to transition from fossil fuels to sustainable, renewable sources of energy. Green hydrogen produced via renewable energy‐driven water electrolysis is an emerging alternative due to its zero emissions and high energy density. To address the high energy consumption of water electrolysis, innovative hybrid electrolyzers integrating nucleophile oxidation reactions (NOR) are under activity investigation, reducing energy demands and enabling valuable product synthesis and waste treatment, thereby enhancing the efficiency and economic viability of hydrogen production via electrocatalytic technologies. Recent advancements in layered hydroxide materials (LHMs) have markedly improved the efficiency of alkaline electrochemical conversion processes and are gaining prominence in NORs due to their expansive surface areas and tailorable characteristics through diverse engineering strategies. Further, their layered architecture is readily conducive to in‐situ characterization, using techniques like XAS, XRD, Raman, and IR spectroscopy, providing insights into their anodic NOR mechanisms. This review summarizes the latest developments in LHMs as electrocatalysts for NOR, discusses current design strategies of LHMs, and emphasizes the significance of operando characterization techniques in elucidating the reaction mechanisms of different LHMs. Finally, the future challenges and potential advancements in their scale‐up application in electrocatalytic NOR are put forward.

Critical Effects of Insoluble Additives in Liquid Electrolytes for Metal Batteries.

Rechargeable metal batteries have received widespread attention due to their high energy density by using pure metal as the anode. However, there are still many fundamental problems that need to be solved before approaching practical applications. The critical ones are low charge/discharge current due to slow ion transport, short cycle lifetime due to poor anode/cathode stability, and unsatisfied battery safety. To tackle these problems, various strategies have been suggested. Among them, electrolyte additive is one of the most widely used strategies. Most of the additives currently studied are soluble, but their reliability is questionable, and they can easily affect the electrochemical process, causing unwanted battery performance decline. On the contrary, insoluble additives with excellent chemical stability, high mechanical strength, and dimensional tunability have attracted considerable research exploration recently. However, there is no timely review on insoluble additives in metal batteries yet. This review summarizes various functions of insoluble additives: ion transport modulation, metal anode protection, cathode amelioration, as well as battery safety enhancement. Future research directions and challenges for insoluble solid additives are also proposed. It is expected this review will stimulate inspiration and arouse extensive studies on further improvement in the overall performance of metal batteries.

Crafting high‐performance polymer‐integrated solid electrolyte for solid state sodium ion batteries

AbstractThe development of modern solid‐state batteries with high energy density has provided the reliable and durable solution needed for over‐the‐air network connectivity devices. In this study, a NASICON‐type Na3Zr2Si2PO12 (NZSP) ceramic filler was prepared using the sol‐gel method and then a polymer‐integrated solid electrolyte consisting of polyethylene oxide (PEO), NZSP, and sodium perborate (SPB) was prepared by Stokes' solution casting process. Through physico‐chemical and electrochemical characterization techniques, the morphology, electrochemical, and thermal properties of the prepared solid electrolyte sample were carefully studied. The PEO/NZSP/SPB electrolyte developed for all‐solid‐state sodium‐ion batteries (ASSSBs) exhibited a strong ionic conductivity, a large window for electrochemical stability, and was effective in controlling the growth of sodium dendrites. Furthermore, the polymer‐integrated solid electrolyte showed impressive rate capability, high discharge capacity (73.2 mAh g−1) at 0.1 mA cm−2, and good faradaic efficiency (98%) even after 100 cycles. These results reveal that the PEO/NZSP/SPB electrolyte is a potential and inevitable candidate for the evolution of high‐performance rechargeable ASSSBs.

Short Multi‐Walled Carbon Nanotubes Loaded Sulfur Nanoparticles for High Performance Lithium‐Sulfur Batteries

AbstractLithium‐sulfur (Li−S) batteries have been regarded as a promising candidate for next‐generation high‐performance energy storage devices because of their advantages in high energy density. However, practical uses of Li−S batteries have been hindered by their poor rate performances and dissatisfactory capacity decay during cycling. In this work, we demonstrate carbon based coating material combined with short multi‐walled carbon nanotubes (S‐CNTs) to form coating cathode (S‐CNTs@S) in the Li−S battery system. The S‐CNTs@S cathode not only facilitates fast diffusion of electrons, but also efficiently inhibits diffusion of poly‐sulfide components. Importantly, the inter‐shell space of S‐CNTs is conducive to the diffusion of electrolyte, which improves the migration efficiency of lithium‐ions, then improves the rated performances of the Li−S battery. Thus, the excellent cycle stability and Coulombic efficiency with high sulfur loading (3 mg cm−2) were demonstrated in durable Li−S coin cell.

Dry Electrode Processing Technology and Binders.

As a popular energy storage equipment, lithium-ion batteries (LIBs) have many advantages, such as high energy density and long cycle life. At this stage, with the increasing demand for energy storage materials, the industrialization of batteries is facing new challenges such as enhancing efficiency, reducing energy consumption, and improving battery performance. In particular, the challenges mentioned above are particularly critical in advanced next-generation battery manufacturing. For batteries, the electrode processing process plays a crucial role in advancing lithium-ion battery technology and has a significant impact on battery energy density, manufacturing cost, and yield. Dry electrode technology is an emerging technology that has attracted extensive attention from both academia and the manufacturing industry due to its unique advantages and compatibility. This paper provides a detailed introduction to the development status and application examples of various dry electrode technologies. It discusses the latest advancements in commonly used binders for different dry processes and offers insights into future electrode manufacturing.

General Fabrication of Robust Alloyed Metal Anodes for High-Performance Metal Batteries.

Revitalizing metal anodes for rechargeable batteries confronts challenges such as dendrite formation, limited cyclicity, and suboptimal energy density. Despite various efforts, a practical fabrication method for dendrite-free metal anodes remains unavailable. Herein, focusing on Li as exemplar, a general strategy is reported to enhance reversibility of the metal anodes by forming alloyed metals, which is achieved by induction heating of 3D substrate, lithiophilic metals, and Li within tens of seconds. It is demonstrated that preferred alloying interactions between substrates and lithiophilic metals created a lithiophilic metal-rich region adjacent to the substrate, serving as ultrastable lithiophilic host to guide dendrite-free deposition, particularly during prolonged high-capacity cycling. Simultaneously, an alloying between lithiophilic metals and Li creates a Li-rich region adjacent to electrolyte that reduces nucleation overpotential and constitutes favorable electrolyte-Li interface. The resultant composite Li anodes paired with high areal loading LiNi0.8Co0.1Mn0.1O2 cathodes achieve superior cycling stability and remarkable energy density above 1200 Wh L-1 (excluding packaging). Furthermore, this approach shows broader applicability to other metal anodes plagued by dendrite-related challenges, such as Na and Zn. Overall, this work paves the way for development of commercially viable metal-based batteries that offer a combination of safety, high energy density, and durability.

Structure-Dependent Water Responsiveness of Protein Block Copolymers.

Biological water-responsive (WR) materials are abundant in nature, and they are used as mechanical actuators for seed dispersal by many plants such as wheat awns and pinecones. WR biomaterials are of interest for applications as high-energy actuators, which can be useful in soft robotics or for capturing energy from natural water evaporation. Recent work on WR silk proteins has shown that β-sheet nanocrystalline domains with high stiffness correlate with the high WR actuation energy density, but the fundamental mechanisms to drive water responsiveness in proteins remain poorly understood. Here, we design, synthesize, and study protein block copolymers consisting of two α-helical domains derived from cartilage oligomeric matrix protein coiled-coil (C) flanking an elastin-like peptide domain (E), namely, CEC. We use these protein materials to create WR actuators with energy densities that outperform mammalian muscle. To elucidate the effect of structure on WR actuation, CEC was compared to a variant, CECL44A, in which a point mutation disrupts the α-helical structure of the C domain. Surprisingly, CECL44A outperformed CEC, showing higher energy density and less susceptibility to degradation after repeated cycling. We show that CECL44A exhibits a higher degree of intermolecular interactions and is stiffer than CEC at high relative humidity (RH), allowing for less energy dissipation during water responsiveness. These results suggest that strong intermolecular interactions and the resulting, relatively steady protein structure are important for water responsiveness.

Tuning the End Alkyl Chain of the Ether Solvent to Stabilize the Electrode/Electrolyte Interfaces in the NCM-Li Battery.

Lithium metal batteries (LMBs) combined with a high-voltage nickel-rich cathode show great potential in meeting the growing need for high energy density. The lack of advanced electrolytes has been a major obstacle in the commercialization of high-voltage lithium metal batteries (LMBs), as these electrolytes need to effectively support both a stable lithium metal anode (LMA) and a high-voltage cathode (>4 V vs Li+/Li). In this work, by extending the two terminal methyl groups in DIGDME and TEGDME to n-butyl groups, we design a new weakly solvating electrolyte (2 M LIFSI+TEGDBE) that enables the stable cycling of NMC83 (LiNi0.83Co0.12Mn0.05O2) cathodes. The NMC83 cell exhibits a high and stable Coulombic efficiency (CE) of over 99%, as well as capacity retention of approximately 99.8% after 100 cycles at 0.3 C. X-ray photoelectron spectroscopy analysis (XPS) and high-resolution transmission electron microscope (HRTEM) images revealed that the anion species decomposed first, resulting in the formation of a cathode-electrolyte interface (CEI) film predominantly consisting of decomposition products from the anions on the positive electrode surface. This work links the functional group of solvents with the solvation structure and electrochemical performance of ether-based electrolytes, providing a distinctive sight to design advanced electrolytes for high-energy-density LMBs.

2D-on-2D Al-Doped NiCo LDH Nanosheet Arrays for Fabricating High-Energy-Density, Wide Voltage Window, and Ultralong-Lifespan Supercapacitors.

Battery-type electrode materials with high capacity, wide potential windows, and good cyclic stability are crucial to breaking through energy storage limitations and achieving high energy density. Herein, a novel 2D-on-2D Al-doped NiCo layered double hydroxide (NiCoAlx LDH) nanosheet arrays with high-mass-loading are grown on a carbon cloth (CC) substrate via a two-step hydro/solvothermal deposition strategy, and the effect of Al doping is employed to modify the deposition behavior, hierarchical morphology, phase stability, and multi-metallic synergistic effect. The optimized NiCoAl0.1 LDH electrode exhibits capacities of 5.43, 6.52, and 7.25 C cm-2 (9.87, 10.88, and 11.15 F cm-2) under 0-0.55, 0-0.60, and 0-0.65V potential windows, respectively, illustrating clearly the importance of the wide potential window. The differentiated deposition strategy reduces the leaching level of Al3+ cations in alkaline solutions, ensuring excellent cyclic performance (108% capacity retention after 40000 cycles). The as-assembled NiCoAl0.1 LDH//activated carbon cloth (ACC) hybrid supercapacitor delivers 3.11 C cm-2 at 0-2.0V, a large energy density of 0.84 mWh cm-2 at a power density of 10.00mW cm-2, and excellent cyclic stability with ≈135% capacity retention after 150000 cycles.

Confined Space Dual-Type Quantum Dots for High-Rate Electrochemical Energy Storage.

Owing to quantum size effect and high redox activity, quantum dots (QDs) play very essential roles toward electrochemical energy storage. However, it is very difficult to obtain different-type and uniformly dispersed high-active QDs in a stable conductive microenvironment, because QDs prepared by traditional methods are mostly dissolved in solution or loaded on the surface of other semiconductors. Herein, dual-type semiconductor QDs (Co9S8 and CdS) are skillfully constructed within the interlayer of ultrathin layered double hydroxides (LDH). Inparticular, the expandable interlayer provides a very suitable confined space for the growth and uniform dispersion of QDs, where Co9S8 originates from in-situ transformation of cobalt atoms in laminate and CdS is generated from interlayer pre-embedding Cd2+. Meanwhile, XAFS and GGA+U calculations are employed to explore and prove the mechanism of QDs formation and energy storage characteristics as compared to surface loading QDs. Significantly, the hybrid supercapacitors achieve high energy density of 329.2 μWh cm-2, capacitance retention of 99.1% and coulomb efficiency of 96.9% after 22,000 cycles, which is superior to the reported QDs-based supercapacitors. These findings provide unique insights for designing and developing stable, ordered, and highly active QDs. This article is protected by copyright. All rights reserved.

Surface Pinning of Mn by Oxidation State Control for the Synthesis of Cobalt-Free, Ni-Rich, Core/Shell Structured Cathode Materials.

Motivated by the increasing cost, environmental concerns, and limited availability of Co, researchers are actively seeking alternative cathode materials for lithium-ion batteries. A promising strategy involves structure-modified materials, such as a NiMn core/shell system. This design leverages the high energy density of a Ni-rich core while employing an Mn-rich shell to enhance interfacial stability by suppressing unwanted reactions with the electrolyte. This approach offers improved cycling stability and reduced reliance on Co. However, the interdiffusion of Mn ions between the core and shell remains a significant challenge during synthesis. This work presents a facile approach to address the issue of Mn interdiffusion in core/shell cathode materials. The study demonstrates that partial oxidation of the precursor during the drying stage effectively enhances the Mn oxidation state. This strategy successfully suppresses Mn interdiffusion during subsequent calcination, leading to the preservation of the core/shell architecture in the final cathode material. This optimized structure mitigates interfacial reactions, enhances chemomechanical properties, and reduces crosstalk, a major contributor to rollover failure. This work presents a novel approach for synthesizing high-performance core/shell cathode materials for next-generation lithium-ion batteries.

Industrial-scale Hard Carbon Designed to Regulate Electrochemical Polarization for Fast Sodium Storage.

Given the merits of abundant resource, low cost and high electrochemical activity, hard carbons have been regarded as one of the most commercializable anode material for sodium-ion batteries (SIBs). However, poor rate capability is one of the main obstacles that severely hinder its further development. In addition, the relationships between preparation method, material structure and electrochemical performance have not been clearly elaborated. Herein, a simple but effective strategy is proposed to accurately construct the multiple structural features in hard carbon via adjusting the components of precursors. Through detailed physical characterization of the hard carbons derived from different regulation steps, and further combined with in-situ Raman and galvanostatic intermittent titration technique (GITT) analysis, the network of multiple relationships between preparation method, microstructure, sodium storage behavior and electrochemical performance have been successfully established. Simultaneously, exceptional rate capability about 108.8 mAh g-1 at 8 A g-1 have been achieved from RHC sample with high reversible capacity and desirable initial Coulombic efficiency (ICE). Additionally, the practical applications can be extended to cylindrical batterywith excellent cycle behaviors. Such facile approach can provide guidance for large-scale production of high-performance hard carbons and provides the possibility of building practical SIBs with high energy density and durability.

Metal Organic Frameworks as Polysulfide Reaction Modulators for Lithium Sulfur Batteries: Advances and Perspectives.

Currently, lithium sulfur (Li-S) battery with high theoretical energy density has attracted great research interest. However, the diffusion and loss process of intermediate lithium polysulfide during charge-discharge hindered the application of the Li-S battery in modern life. To overcome this issue, metal organic frameworks (MOFs) and their composites have been regarded as effective additions to restrain the LiPS diffusion process for Li-S battery. Benefiting from the unique structure with rich active sites to adsorb LiPS and accelerate the LiPS redox, the Li-S batteries with MOFs modified exhibit superior electrochemical performance. Considering the rapid development of MOFs in Li-S battery, this review summarizes the recent studies of MOFs and their composites as the sulfur host materials, functional interlayer, separator coating layer, and separator/solid electrolyte for Li-S batteries in detail. In addition, the promising design strategies of functional MOF materials are proposed to improve the electrochemical performance of Li-S battery.

Hydrogen storage methods by lithium borohydride

This paper addresses the urgent need for efficient hydrogen storage methods in the context of combating climate change and transitioning to sustainable energy sources. Among various storage options, LiBH4 is highlighted for its high volumetric and gravimetric energy densities, critical factors in determining its suitability for energy applications. However, challenges arise due to its high thermolysis temperature, which poses difficulties, especially in applications like automotive use where high temperatures are required. The commercial viability of LiBH4 remains a significant obstacle due to the nascent stage of chemical hydride technology and the absence of large-scale production facilities. Environmental concerns also loom large, as the production of LiBH4 relies on extensive mining of lithium and boron, known for their environmental impact. Furthermore, the economic feasibility of LiBH4 as a hydrogen storage medium is questioned, given the substantial portion of total expenses attributed to hydrogen costs, affecting all methods except those based on fossil fuels or electricity. Nevertheless, there is optimism that with technological advancements and improved infrastructure, the costs associated with LiBH4 and hydrogen storage overall may decrease over time.In conclusion, while LiBH4 presents promising energy density characteristics, its practical implementation faces challenges such as high production costs, environmental concerns, and technological limitations. Overcoming these obstacles is crucial for realizing a sustainable and carbon-free energy landscape driven by hydrogen.

The effect of temperature on the co-combustion of hydrochar and NH3 using the ReaxFF method

The utilization of NH3, a carbon-free hydrogen carrier, can be optimized through its co-combustion with solids. However, prior studies have primarily focused on coal as the solid fuel, which entails its consumption. Considering that hydrochar possesses abundant oxygen-containing functional groups, as well as high mass and energy density, it presents itself as a promising alternative solid fuel to coal, thereby decreasing dependence on fossil fuels. Therefore, this study investigates the co-combustion of different proportions of hydrochar, NH3, and O2. Molecular dynamic simulations using the ReaxFF MD method were conducted to investigate the impact of temperature on combustion by analyzing product distribution, evolution of bonds, and gas characteristic curves. Additionally, N migration was examined to elucidate the processes leading to the generation of N2 and NOx from NH3. The results showed that temperature facilitated the progression of combustion as the total number of molecules increased (from 2614 at 2000 K to 3137 at 2500 K) and variety of products expanded (from 48 at 2000 K to 69 at 2500 K) with increasing temperature. With increasing temperature, the descent rate of NH3 and oxygen accelerated, whereas the quantities of H2 and H2O increased. Furthermore, during combustion, hydrochar underwent three stages: initial coke formation, subsequent tar generation, and organic gas production. Second, during N migration, hydrochar directly or indirectly participated in the formation of N2. In this process, hydrochar indirectly contributed to the formation of NH and NH2 intermediates, leading to the formation of N2. In contrast, the majority of NO was formed through the direct decomposition of hydrochar. Finally, because of the limited quantity of generated NO2, N existed primarily in the form of N2 and NO. These findings provide theoretical guidance for the combustion of NH3 using hydrochar.

Time for mixing: Mixed dicationic energetic salts based on methylene bridged 4-hydroxy-3,5-dinitropyrazole and tetrazole for tunable performance

Various types of materials have been explored in the pursuit of high energy density materials (HEDMs) that have balanced energy and stability. Among them, energetic salts show numerous advantages, such as lower vapor pressures, high physical stabilities, and the opportunity for favorable tuning by careful selection of cations/anions. Nitrogen-rich bases are generally used as cations for energetic salt formation. While the synthesis of salts with larger cations lowers the sensitivity, smaller cations aid better energetic performance. A combination of both in the same ionic moieties might help in the formation of a superior explosive. In this work, a facile route for the synthesis of mixed dicationic energetic salts based on 1-((1H-tetrazol-5-yl)methyl)-3,5-dinitro-1H-pyrazol-4-ol (compound 1) has been explored by various combinations of bigger and smaller cations (compounds 4–10). All the synthesized energetic salts showed high positive heats of formation, energetic performance comparable to TATB, excellent stability towards impact and friction, and acceptable thermal stabilities. This improved technique will provide an additional option for fine-tuning the energetic properties of HEDMs and will facilitate in exploring the role of various cations in the overall performance of the energetic compounds.

An anode-free sodium dual-ion battery

Batteries with both high energy and power densities are desired for practical applications. Constructing anode-free batteries is effective to achieve high energy density, yet remains highly challenging to obtain high power density simultaneously. To overcome this dilemma, dual-ion storage strategy is introduced to anode-free battery. As a proof of concept, an anode-free sodium dual-ion battery (AFSDIB) with combined high energy and power densities is successfully fabricated. Plasma-treated current collector (Al/N-C) exhibits a sodiophilic N-doped carbon surface, enabling highly reversible Na plating/stripping at high current densities. Meanwhile, the sluggish desolvation process is intrinsically eliminated at the polytriphenylamine (PTPAn) cathodic side owing to the solvation-free anion storage chemistry. Consequently, the assembled Al/N-C||PTPAn AFSDIB exhibits a remarkable energy density over 380 Wh kg−1 (at 375 W kg−1) and power density above 1800 W kg−1 (at 302 Wh kg−1) based on active materials and consumed electrolyte, which is superior to the reported state-of-the-art anode-free and dual-ion sodium batteries. This work paves a new pathway for developing batteries with both high energy and power densities.

High-Entropy Configuration Strategy to Build High Performance Na-Ion Layered Oxide Cathodes Derived from Simple Techniques.

Layered transition metal oxides are commonly used as the cathode materials in sodium-ion batteries due to their low cost and easy manufacturing. However, the application is hindered by poor rate performance and complex phase transitions. To address these challenges, a new seven-component high-entropy layered oxide cathode material, O3-NaNi0.25Fe0.15Mn0.3Ti0.1Sn0.05Co0.05Li0.1O2 (HEO) has been developed. The entropy stabilization effect plays a crucial role in improving the performance of electrochemical systems and the stability of structures. The HEO exhibits a specific discharge capacity of 154.1 mA h g-1 at 0.1 C and 94.5 mA h g-1 at 7 C. In-situ and ex-situ XRD results demonstrate that the HEO effectively retards complex phase transitions. This work provides a high-entropy design for the storage materials with a high energy density. Meanwhile, it eliminates industry doubts about the performance of sodium ion layered oxide cathode materials.

Relay-Type Catalysis by a Dual-Metal Single-Atom System in a Waste Biomass Derivative Host for High-Rate and Durable Li-S Batteries.

An environmental-friendly and sustainable carbon-based host is one of the most competitive strategies for achieving high loading and practicality of Li-S batteries. However, the polysulfide conversion reaction kinetics is still limited by the nonuniform or monofunctional catalyst configuration in the carbon host. In this work, we propose a catalysis mode based on "relay-type" co-operation by adjacent dual-metal single atoms for high-rate and durable Li-S batteries. A discarded sericin fabric-derived porous N-doped carbon with a stacked schistose structure is prepared as the high-loading sulfur (84 wt %) host by a facile ionothermal method, which further enables the uniform anchoring of Fe/Co dual-metal single atoms. This multifunctional host enables superior lithiophilic-sulfiphilic and electrocatalytic capabilities contributed by the "relay-type" single-atom modulation effects on different conversion stages of liquid polysulfides and solid Li2S2/Li2S, leading to the suppression of the "shuttle effect", alleviation of nucleation and decomposition barriers of Li2Sx, and acceleration of polysulfide conversion kinetics. The corresponding Li-S batteries exhibit a high specific capacity of 1399.0 mA h g-1, high-rate performance up to 10 C, and excellent cycling stability over 1000 cycles. They can also endure the high sulfur loading of 8.5 mg cm-2 and the lean electrolyte condition and yield an areal capacity as high as 8.6 mA h cm-2. This work evidentially demonstrates the potential of waste biomass reutilization coupled with the design of a single-atom system for practical Li-S batteries with high energy density.