Materials For Rechargeable Batteries Research Articles

Electron paramagnetic resonance as a tool to determine the sodium charge storage mechanism of hard carbon

Hard carbon is a promising negative electrode material for rechargeable sodium-ion batteries due to the ready availability of their precursors and high reversible charge storage. The reaction mechanisms that drive the sodiation properties in hard carbons and subsequent electrochemical performance are strictly linked to the characteristic slope and plateau regions observed in the voltage profile of these materials. This work shows that electron paramagnetic resonance (EPR) spectroscopy is a powerful and fast diagnostic tool to predict the extent of the charge stored in the slope and plateau regions during galvanostatic tests in hard carbon materials. EPR lineshape simulation and temperature-dependent measurements help to separate the nature of the spins in mechanochemically modified hard carbon materials synthesised at different temperatures. This proves relationships between structure modification and electrochemical signatures in the galvanostatic curves to obtain information on their sodium storage mechanism. Furthermore, through ex situ EPR studies we study the evolution of these EPR signals at different states of charge to further elucidate the storage mechanisms in these carbons. Finally, we discuss the interrelationship between EPR spectroscopy data of the hard carbon samples studied and their corresponding charging storage mechanism.

Identifying the plateau sodium storage behavior of hard carbon through the spin state

Hard carbon has emerged as a promising anode material for rechargeable sodium-ion batteries, owing to its abundant precursor sources and remarkable reversible charge storage capacity. The key to achieving an extended sodium storage capacity lies in the plateau capacity largely associated with the closed-pore structure, yet a comprehensive understanding in this area remains incomplete. In our study, we utilized electron paramagnetic resonance (EPR) spectra to discern the spin state of unpaired electrons within hard carbon materials, enabling the identification of sodium storage plateau regions. Hard carbon anodes with plateau capacity predominantly exhibit delocalized spins, evident in the EPR spectrum by limited spin density and a linewidth exceeding 100 G. These spins originate from the extended aromatic structure within small-sized but curved nano-graphite and the closed-pore walls, which are crucial for plateau capacity. Conversely, hard carbon anodes exclusively possessing slope capacity are characterized by localized spins, presenting a typical narrow and intense Lorentzian EPR signal. These localized spins arise from the edge defects of the nano-graphite structure, serving as favourable sites for sodium adsorption. Our development of a methodology to discern hard carbon plateau capacity behavior based on EPR spectra presents a facile and rapid approach for advancing high-performance hard carbon materials.

Accessing Mg‐Ion Storage in V2PS10 via Combined Cationic‐Anionic Redox with Selective Bond Cleavage

AbstractMagnesium batteries attract interest as alternative energy‐storage devices because of elemental abundance and potential for high energy density. Development is limited by the absence of suitable cathodes, associated with poor diffusion kinetics resulting from strong interactions between Mg2+ and the host structure. V2PS10 is reported as a positive electrode material for rechargeable magnesium batteries. Cyclable capacity of 100 mAh g−1 is achieved with fast Mg2+ diffusion of 7.2 10−11–4 10−14 cm2 s−1. The fast insertion mechanism results from combined cationic redox on the V site and anionic redox on the (S2)2− site; enabled by reversible cleavage of S−S bonds, identified by X‐ray photoelectron and X‐ray absorption spectroscopy. Detailed structural characterisation with maximum entropy method analysis, supported by density functional theory and projected density of states analysis, reveals that the sulphur species involved in anion redox are not connected to the transition metal centres, spatially separating the two redox processes. This facilitates fast and reversible Mg insertion in which the nature of the redox process depends on the cation insertion site, creating a synergy between the occupancy of specific Mg sites and the location of the electrons transferred.

Accessing Mg-Ion Storage in V2PS10 via Combined Cationic-Anionic Redox with Selective Bond Cleavage.

Magnesium batteries attract interest as alternative energy-storage devices because of elemental abundance and potential for high energy density. Development is limited by the absence of suitable cathodes, associated with poor diffusion kinetics resulting from strong interactions between Mg2+ and the host structure. V2PS10 is reported as a positive electrode material for rechargeable magnesium batteries. Cyclable capacity of 100 mAh g-1 is achieved with fast Mg2+ diffusion of 7.2 10-11-4 10-14 cm2 s-1. The fast insertion mechanism results from combined cationic redox on the V site and anionic redox on the (S2)2- site; enabled by reversible cleavage of S-S bonds, identified by X-ray photoelectron and X-ray absorption spectroscopy. Detailed structural characterisation with maximum entropy method analysis, supported by density functional theory and projected density of states analysis, reveals that the sulphur species involved in anion redox are not connected to the transition metal centres, spatially separating the two redox processes. This facilitates fast and reversible Mg insertion in which the nature of the redox process depends on the cation insertion site, creating a synergy between the occupancy of specific Mg sites and the location of the electrons transferred.

Dynamic Molecular Interphases Regulated by Trace Dual Electrolyte Additives for Ultralong-Lifespan and Dendrite-Free Zinc Metal Anode.

Metallic zinc is a promising anode material for rechargeable aqueous multivalent metal-ion batteries due to its high capacity and low cost. However, the practical use is always beset by severe dendrite growth and parasitic side reactions occurring at anode/electrolyte interface. Here we demonstrate dynamic molecular interphases caused by trace dual electrolyte additives of D-mannose and sodium lignosulfonate for ultralong-lifespan and dendrite-free zinc anode. Triggered by plating and stripping electric fields, the D-mannose and lignosulfonate species are alternately and reversibly (de-)adsorbed on Zn metal, respectively, to accelerate Zn2+ transportation for uniform Zn nucleation and deposition and inhibit side reactions for high Coulombic efficiency. As a result, Zn anode in such dual-additive electrolyte exhibits highly reversible and dendrite-free Zn stripping/plating behaviors for >6400 hours at 1 mA cm-2, which enables long-term cycling stability of Zn||ZnxMnO2 full cell for more than 2000 cycles.

Research progress on lignin-based carbon electrode materials in rechargeable batteries

Lignin, with its carbon content of up to 60%, can be an ideal precursor for the preparation of carbon materials. Carbonaceous materials obtained from lignin can be transformed into porous and structural morphologies at different scales, providing a biomass approach to energy conversion and storage in batteries. Focusing on lignin-derived carbon materials, this paper summarizes the different morphologies and structures of lignin-based carbon obtained through different preparation methods, and the different electrochemical properties exhibited by these materials as electrode materials for rechargeable batteries (lithium-ion batteries, sodium-ion batteries, lithium-sulphur batteries, etc.). In addition, the development prospects and challenges of lignin-based carbon materials in the field of rechargeable batteries are summarized, providing ideas for the next step in the design and development of high-performance lignin-based carbon-based electrode materials.

CoNi hexacyanoferrate nanoparticles anchored on carbon nanotubes as superior cathode materials for rechargeable aqueous zinc-ion batteries

Prussian blue analogues (PBAs) have attracted growing interest as competitive cathode materials for aqueous zinc-ion batteries (AZIBs). However, their low conductivity and easy structural collapse often lead to poor reversible capacity and cyclability. Herein, cobalt‑nickel hexacyanoferrate (CoNiHCF), a CoNi-Prussian blue analogue, are designed as AZIBs cathode materials for the first time, in which highly uniform CoNiHCF nanocubes are in-situ decorated on carbon nanotubes (CNTs) via a simple co-precipitation method. The resulted CoNiHCF/CNTs composite displays superior zinc ion storage performance, with a great reversible capacity of 124.9 mAh g−1 at the current density of 50 mA g−1, and a high capacity retention of 81.8 % at 3000 mA g−1 for 1000 cycles, which are remarkably superior to those of CoHCF, NiHCF and CoNiHCF. The excellent Zn2+ storage properties of CoNiHCF/CNTs can be ascribed to the bimetallic synergistic effect of Co and Ni as well as the introduction of conductive CNTs skeleton. This study offers a straightforward and efficient method for promoting the application of PBAs-based cathodes in AZIBs.

Microwave-induced defect-rich vanadium sulfide cathodes for highly reversible electrochemical magnesium storage

Vanadium sulfide (VS4) demonstrates the most prospect as the cathode materials for rechargeable magnesium battery due to its special one-dimensional linear crystal structure. However, VS4 cathode still suffers from sluggish kinetics, irreversible structural change, short cycle life, and low capacity. Herein, a microwave-induced synthesis method is presented to fabricate VS4 nanosheets with rich sulfur vacancies and high V3+/V4+ ratio. When serviced as the cathode material for rechargeable magnesium battery, the VS4 nanosheets display excellent electrochemical performances with large specific capacity of 701 mAh/g at 200 mA g−1 current density. In addition, the VS4 nanosheets cathodes also show long-term operating stability over 600 cycles at 1.0 A/g current density with only 0.3 % capacity decay per cycle. Our experimental results show that the improved electrochemical reaction kinetics is ascribed to the defect-rich structure and the reversible anionic redox reactions between S2−/S22− of the VS4 nanosheets. This work offers a meaningful way to design high-performance Mg2+ ion storage cathode materials with favorable diffusion kinetics.

Facile Synthesis of Diazaanthraquinone Dimers as High-Capacity Organic Cathode Materials for Rechargeable Lithium Batteries.

Organic cathode materials (OCMs) have tremendous potential to construct sustainable and highly efficient batteries beyond conventional Li-ion batteries. Thereinto, quinone/pyrazine hybrids show significant advantages in material availability, energy density, and cycling stability. Herein, we propose a facile method to synthesize quinone/pyrazine hybrids, i.e., the condensation reaction between ortho-diamine and bromoacetyl groups. Based on it, we have successfully synthesized three 1,4-diazaanthraquinone (DAAQ) dimers, including 2,2'-bi(1,4-diazaanthraquinone) (BDAAQ) with an exceptional theoretical capacity of 512 mAh g-1 based on the eight-electron reaction. It can be fully utilized in Li batteries in a wide voltage range of 0.8-3.8 V, at the cost of inferior cycling stability. In an optimal voltage range of 1.4-3.8 V, BDAAQ exhibits one of the best comprehensive electrochemical performances for small-molecule OCMs, including a high specific capacity of 366 mAh g-1, an average discharge voltage of 2.26 V, as well as a respectable capacity retention of 59% after 500 cycles. Moreover, the in-depth investigations reveal the redox reaction mechanisms based on C═O and C═N groups as well as the capacity fading mechanisms based on dissolution-redeposition behaviors. In brief, this work provides an instructive synthesis method and mechanism understanding of high-performance OCMs based on a quinone/pyrazine hybrid structure.

A Perspective of Bioinspired Interfaces Applied in Renewable Energy Storage and Conversion Devices.

The natural world renders a large number of opportunities to design intriguing structures and fascinating functions for innovations of advanced surfaces and interfaces. Currently, bioinspired interfaces have attracted much attention in practical applications of renewable energy storage and conversion devices including rechargeable batteries, fuel cells, dye-sensitized solar cells, and supercapacitors. By mimicking miscellaneous natural creatures, many novel bioinspired interfaces with various components, structures, morphology, and configurations are exerted on the devices' electrodes, electrolytes, additives, separators, and catalyst matrixes, resorting to their wonderful mechanical, optical, electrical, physical, chemical, and electrochemical features compared with the corresponding traditional modes. In this Perspective, the principles of designing bioinspired interfaces are discussed with respect to biomimetic chemical components, physical morphologies, biochemical reactions, and macrobiomimetic assembly configurations. A brief summary, subsequently, is mainly focused on the recent progress on bioinspired interfaces applied in key materials for rechargeable batteries. Ultimately, a critical comment is projected on significant opportunities and challenges existing in the future development course of bioinspired interfaces. It is expected that this Perspective is able to provide a profound perception into some underlying artificial intelligent energy storage and conversion device design as a promising candidate to resolve the global energy crisis and environmental pollution.

Polypyrrole pre-intercalation engineering-induced NH4+ removal in tunnel ammonium vanadate toward high-performance zinc ion batteries

Ammonium vanadate with stable bi-layered structure and superior mass-specific capacity have emerged as competitive cathode materials for aqueous rechargeable zinc-ion batteries (AZIBs). Nevertheless, fragile NH…O bonds and too strong electrostatic interaction by virtue of excessive NH4+ will lead to sluggish Zn2+ ion mobility, further largely affects the electro-chemical performance of ammonium vanadate in AZIBs. The present work incorporates polypyrrole (PPy) to partially replace NH4+ in NH4V4O10 (NVO), resulting in the significantly enlarged interlayers (from 10.1 to 11.9 Å), remarkable electronic conductivity, increased oxygen vacancies and reinforced layered structure. The partial removal of NH4+ will alleviate the irreversible deammoniation to protect the laminate structures from collapse during ion insertion/extraction. The expanded interlayer spacing and the increased oxygen vacancies by the virtue of the introduction of polypyrrole improve the ionic diffusion, enabling exceptional rate performance of NH4V4O10. As expected, the resulting polypyrrole intercalated ammonium vanadate (NVOY) presents a superior discharge capacity of 431.9 mAh g−1 at 0.5 A g−1 and remarkable cycling stability of 219.1 mAh g−1 at 20 A g−1 with 78 % capacity retention after 1500 cycles. The in-situ electrochemical impedance spectroscopy (EIS), in-situ X-ray diffraction (XRD), ex-situ X-ray photoelectron spectroscopy (XPS) and ex-situ high resolution transmission electron microscopy (HR-TEM) analysis investigate a highly reversible intercalation Zn-storage mechanism, and the enhanced the redox kinetics are related to the combined effect of interlayer regulation, high electronic conductivity and oxygen defect engineering by partial substitution NH4+ of PPy incorporation.

2D organic-inorganic supercrystalline structures with 3D layered ion channels for efficient aqueous zinc ion storage

Aqueous zinc ion batteries (AZIBs) have become powerful substitutes for large-scale energy storage because of their high safety and low cost, so the design of high-performance cathode materials has always been a requirement. Layered VxOy is one key type of cathode materials for rechargeable AZBs. Usually, it shows two-dimensional (2D) ion diffusion mechanism through the intercalation/deintercalation of Zn2+ at edge sites, but is plagued by the inert basal planes. Here, polymelamine (PME) was successfully inserted into the layered structure of VO2 nH2O and an organic–inorganic supercrystalline structure (PMVO-sls) with layered structure along the c-axis and ab plane was formed, thus providing additional ion diffusion channels and abundant active sites. The highly efficient and ultrafast 3D Zn2+ intercalation/deintercalation behaviors along both the c-axis and ab plane of VO2 nH2O are realized for the first time in AZIBs. Moreover, PMVO-sls has rich oxygen vacancy (Od) which is beneficial to electrolyte transport and ion diffusion, and it is a very competitive electrode material. Experimental data and density functional theory calculation (DFT) have confirmed that the intercalation of PEM can improve the electronic conductivity of materials and explained the possibility of Zn2+ diffusion through 3D interlayer structural channels. As cathode materials for AZIBs in 3 M Zn (CF3SO3)2, PMVO-sls exhibited an ideal reversible capacity of 344 mA h g−1 at 0.2 A g−1, and excellent cyclic stability (121 mA h g−1 retained after 4,500 cycles at 10 A g−1, a retention rate of 93%). Furthermore, in PMVO-sls/2.8 M Zn (CF3SO3)2 + 0.2 M ZnSO4/Zn AZIBs, PMVO-sls has a higher reversible capacity with an reversible capacity of 392.1 mA h g−1 at 0.2 A g−1 and better cyclic stability (180 mA h g−1 retained after 6,000 cycles at 10 A g−1, a retention rate of 90%). This method can provide a new way for the synthesis of high quality cathode materials for AZIBs and other metal ion batteries.

Vertically Aligned Conductive Metal–Organic Frameworks with Switchable Electrical Conductivity for Li Metal Anode

AbstractLithium (Li) metal, with its unparalleled theoretical capacity and lowest electrochemical potential, is a promising anode material for rechargeable batteries. Yet, challenges such as dendrite formation, severe electrode volume change, and ongoing Li consumption impede its practical adoption. To address these challenges, a novel approach is introduced, harnessing the switchable electrical conductivity of a nanoporous current collector for Li metal anode. A vertically aligned Nickel‐catecholate (VANC) is directly grown on the copper foil as the nanoporous current collector, and the Li intercalation and de‐intercalation of VANC reversibly decrease and increase the electrical conductivity in the direction perpendicular to the electrode, respectively. The switchable conductivity induces uniform deposition and stripping of Li metal without forming dendrite and dead Li during the Li plating/stripping process and thus enables high coulombic efficiency of over 98% even after 200 cycles. This nanoporous structure with switchable conductivity will open up a new path for reliable lithium metal anode for rechargeable battery applications.

Hybrid Organosulfur Cathode Materials for Rechargeable Lithium Batteries

Hybrid Organosulfur Cathode Materials for Rechargeable Lithium Batteries

Solvent-Free Reaction for Unsymmetrical Organodisulfides with High Purity and Application as Cathode-Active Materials.

Unsymmetrical disulfides, in which different organic groups are bonded to disulfide bonds, have been synthesized by cross-coupling reactions using thiols as substrates. However, due to the low-binding energy of unsymmetrical disulfides, its disproportionation occurs based on the side reactions with nucleophilic thiols, resulting in the impurity of symmetric disulfides. In this study, we developed a solvent-free synthesis method for unsymmetrical disulfides using thiosulfonates, thiols, and a base. This synthetic method enabled us to obtain highly pure diaryl-substituted unsymmetrical disulfides with particularly low-binding energy without control over the nucleophilicity and elimination properties of the substrate. Furthermore, it was observed that the disproportionation of unsymmetrical disulfides occurred in the solvent. This means that solvent-free condition is one of the factors to obtain unsymmetrical disulfides. As a new application of unsymmetrical disulfides, we applied unsymmetrical disulfides to cathode active materials of lithium batteries based on the reversible multi-electron redox activity of S-S bonds. The batteries using unsymmetrical disulfide cathode-active materials with a carbon nanotube exhibited initial capacities of 127 and 158 Ah/kg, equal to 42 and 53% of their theoretical ones. We demonstrated that unsymmetrical disulfides could be used as cathode-active materials for rechargeable batteries.

Perylenetetracarboxylic Diimide Composite Electrodes as Organic Cathode Materials for Rechargeable Sodium-Ion Batteries: A Joint Experimental and Theoretical Study.

The organic semiconductor 3,4,9,10-perylenetetracarboxylic diimide (PTCDI), a widely used industrial pigment, has been identified as a diffusion-less Na-ion storage material, allowing for exceptionally fast charging/discharging rates. The elimination of diffusion effects in electrochemical measurements enables the assessment of interaction energies from simple cyclic voltammetry experiments through the theoretical work of Laviron and Tokuda. In this work, the two N-substituted perylenes, N,N'-dimethyl-3,4,9,10-perylenetetracarboxylic diimide (Me2PTCDI) and N,N'-diphenyl-3,4,9,10-perylenetetracarboxylic diimide (Ph2PTCDI), as well as the parent molecule 3,4,9,10-perylenetetracarboxylic diimide (H2PTCDI) are investigated as thin-film composite electrodes on carbon fibers for sodium-ion batteries. The composite electrodes are analyzed with Raman spectroscopy. Interaction parameters are extracted from cyclic voltammetry measurements. The stability and rate capability of the three PTCDI derivatives are examined through galvanostatic measurements in sodium-ion half-cell batteries and the influence of the interactions on those parameters is evaluated. In addition, self-consistent charge density function tight binding calculations of the different PTCDI systems interacting with graphite have been carried out. The results show that the binding motif displays notable deviations from an ideal ABA stacking, especially for the neutral state. In addition, data obtained for the electron-transfer integrals show that the difference in performance between different PTCDI thin-film batteries cannot be solely explained by the electron-transfer properties and other factors such as H-bonding have to be considered.

Phenyl Tellurosulfides as Cathode Materials for Rechargeable Lithium Batteries.

Phenyl ditelluride (PDTe) as a cathode material for rechargeable batteries has a low specific capacity (130.9 mAh g-1) due to limited active sites (two). To increase its capacity, additional active species need to be added to the structure of PDTe, like sulfur. Here, phenyl tellurosulfide (PDTeS) and phenyl tellurodisulfide (PDTeS2) can be formed via addition reactions and have specific capacities of 242.8 and 339.6 mAh g-1, respectively. The products are characterized by mass spectrometry and Raman spectroscopy. The Li/PDTeSn (n = 1-2) cells exhibit high material utilization (>85%) and unique redox mechanism. They can be cycled stably for more than 1000 cycles at an areal mass loading of 1.1 mg cm-2 and maintain capacity retentions of >72% after 100 cycles with PDTeSn loading of ∼6 mg cm-2. Moreover, the Li/PDTeS2 cell achieves a specific energy of up to 695 Wh kg-1 even when the electrolyte/PDTeS2 ratio is as low as 2.5 μL mg-1. The successful synthesis and application of PDTeSn prove that they are promising cathode materials for rechargeable lithium batteries.

Aqueous Zn-Tetrazine Batteries with Cooperative Zn2+/H+ Insertion.

We present the investigation of 1,2,4,5-tetrazine derivatives as low-cost and synthetically modular organic electrode materials in rechargeable aqueous Zn-ion batteries (AZIBs). The substituents at the 3,6-positions of tetrazine were found to be critical for cycling stability. While heteroatom substituents (chloro, methoxy, and pyrazole) lead to the rapid decomposition of electrode materials in the electrolyte, the installation of phenyl groups enhances the cycling stability via π-π stacking. Spectroscopic characterization suggests a cooperative Zn2+ and H+ insertion mechanism. This unique cooperativity of Zn2+ and H+ leads to a steady discharge plateau in contrast to the undesirable sloping voltage profile typically observed in Zn-organic batteries.

Benzoquinone-Lubricated Intercalation in Manganese Oxide for High-Capacity and High-Rate Aqueous Aluminum-Ion Battery.

Aqueous aluminum-ion batteries are attractive post-lithium battery technologies for large-scale energy storage in virtue of abundant and low-cost Al metal anode offering ultrahigh capacity via a three-electron redox reaction. However, state-of-the-art cathode materials are of low practical capacity, poor rate capability, and inadequate cycle life, substantially impeding their practical use. Here layered manganese oxide that is pre-intercalated with benzoquinone-coordinated aluminum ions (BQ-AlxMnO2) as a high-performance cathode material of rechargeable aqueous aluminum-ion batteries is reported. The coordination of benzoquinone with aluminum ions not only extends interlayer spacing of layered MnO2 framework but reduces the effective charge of trivalent aluminum ions to diminish their electrostatic interactions, substantially boosting intercalation/deintercalation kinetics of guest aluminum ions and improving structural reversibility and stability. When coupled with Zn50Al50 alloy anode in 2m Al(OTf)3 aqueous electrolyte, the BQ-AlxMnO2 exhibits superior rate capability and cycling stability. At 1Ag-1, the specific capacity of BQ-AlxMnO2 reaches ≈300mAhg-1 and retains ≈90% of the initial value for more than 800 cycles, along with the Coulombic efficiency of as high as ≈99%, outperforming the AlxMnO2 without BQ co-incorporation.

One-dimensional van der Waals V2Se9 as a conversion-type anode material for advanced Li rechargeable batteries

Volume expansion of active materials during lithium storage is one of the main issues in Li-ion batteries (LIBs) that should be addressed. In particular, large volume changes and particle cracking are problematic for electrode materials based on conversion reaction, which are considered attractive anode materials with high energy densities. In this study, a one-dimensional van der Waals (1D vdW) material, V2Se9, is proposed as a conversion-type anode material for LIBs. The V2Se9 electrode material has a 1D chain molecular structure with vdW interactions between chains to form a bulk crystal structure. The spaces between the 1D chains act as structural buffers and provide short Li+ diffusion paths that can improve the electrochemical performance of the electrode materials. The V2Se9 electrode exhibits a high reversible capacity of 563.3 mAh g−1 at 100 mA g−1 and a high rate capability of 109.1 mAh g−1 at 3200 mA g−1. The capacity retention of V2Se9 electrodes is 83.72% after 100 cycles. Synchrotron X-ray diffraction and X-ray absorption spectroscopy reveal the formation of Li2Se and V metal, indicating that Li ion storage occurs via the conversion reaction. The structural stability of V2Se9 is demonstrated using SEM measurements of the discharged and charged V2Se9 electrodes during cycling. These results demonstrate the reaction mechanism of V2Se9 and highlight the potential of 1D vdW materials as high-performance anode materials in LIBs.