Intercalation Chemistry Research Articles

Ultrahigh-energy and -power aqueous rechargeable zinc-ion microbatteries based on highly cation-compatible vanadium oxides

• Aqueous Zn-ion microbatteries are constructed by nanoporous metal/oxide electrodes. • Cation insertion/extraction kinetics depends on host/guest compatibility. • Zn x V 2 O 5 supported by nanoporous Au shows the highest capacity and rate capability. • Zn-ion microbatteries of nanoporous Au/Zn x V 2 O 5 outperform the present microdevices. Aqueous multivalent-metal-ion intercalation chemistries hold genuine promise to develop safe and powerful microbatteries for potential use in many miniaturized electronics. However, their development is beset by state-of-the-art electrode materials having practical capacities far below their theoretical values. Here we demonstrate that high compatibility between layered transition-metal oxide hosts and hydrated cation guests substantially boost their multi-electron-redox reactions to offer higher capacities and rate capability, based on typical bipolar vanadium oxides preintercalated with hydrated cations (M x V 2 O 5 ). When seamlessly integrated on Au current microcollectors with a three-dimensional bicontinuous nanoporous architecture that offers high pathways of electron transfer and ion transport, the constituent Zn x V 2 O 5 exhibits specific capacity of as high as ∼527 mAh g −1 at 5 mV s −1 and retains ∼300 mAh g −1 at 200 mV s −1 in 1 M ZnSO 4 aqueous electrolyte, outperforming the M x V 2 O 5 (M = Li, Na, K, Mg). This allows aqueous rechargeable zinc-ion microbatteries constructed with symmetric nanoporous Zn x V 2 O 5 /Au interdigital microelectrodes as anode and cathode to show high-density energy of ∼358 mWh cm −3 (a value that is forty-fold higher than that of 4 V/500 μAh Li thin film battery) at high levels of power delivery.

Understanding intercalation chemistry for sustainable aqueous zinc–manganese dioxide batteries

Rechargeable aqueous Zn–MnO2 technology combines one of the oldest battery chemistries with favourable sustainability characteristics, including safety, cost and environmental compatibility. However, the ambiguous charge storage mechanism presents a challenge to fulfil the great potential of this energy technology. Here we leverage on advanced electron microscopy, electrochemical analysis and theoretical calculations to look into the intercalation chemistry within the cathode material, or α-MnO2 more specifically. We show that Zn2+ insertion into the cathode is unlikely in the aqueous system; rather, the charge storage process is dominated by proton intercalation to form α-HxMnO2. We further reveal anisotropic lattice change as a result of entering protons proceeding from the surface into the bulk of α-MnO2, which accounts for the structural failure and capacity decay of the electrode upon cycling. Our work not only advances the fundamental understanding of rechargeable zinc batteries but also suggests the possibility to optimize proton intercalation kinetics for better-performing cell designs. A rechargeable aqueous Zn–MnO2 battery features a combination of favourable sustainability characteristics from safety to cost. The authors deploy advanced characterizations and theoretical calculations to provide fresh insight into the charge storage mechanism, which not only closes an ongoing debate but suggests ways forward.

Discrete Graphitic Crystallites Promise High‐rate Ion Intercalation for KC8 Formation in Potassium Ion Batteries

AbstractGraphite has paved the way for commercial lithium‐ion batteries and shows great potential as an anode for high‐energy potassium‐ion batteries (PIBs) due to its low‐potential charge/discharge plateau. However, the restricted diffusion of large K+ in graphite causes difficulties in generating the stage‐one graphite‐intercalation compound (GIC) KC8 at high rates and results in a low plateau capacity and an inferior rate performance. It is discovered that the formation of high‐stage GICs (prior to KC24) is the rate‐controlling step of K+ intercalation, which is key to forming KC8. Here, a carbon anode material containing the medium‐size discrete graphitic crystallites is reported, produced by heating non‐graphitizable carbon above 2800 °C. This carbon anode material promotes the formation of KC8 due to the accelerated K+ diffusion especially at the rate‐controlling step and the sufficient reactive sites, which leads to a record‐high plateau capacity of 293 mAh g−1 and an excellent rate performance with 180 mAh g−1 at 500 mA g−1. For comparison, the respective values for graphite are only 242 and 51 mAh g−1. This study provides new insights into K+‐intercalation chemistry and shall promote the design of carbon anode materials for high‐energy and high‐power PIBs and even other energy storage systems.

Efficient high-rate aqueous alkaline battery with dual-ion intercalation chemistry enabled by asymmetric electrode polarization

Aqueous batteries hold promise for grid energy storage for their intrinsic safety and cost effectiveness. Suppressing water electrolysis is a prime consideration, while the round-trip efficiency is an often-overlooked issue. Here, we report an aqueous alkaline dual-ion battery with Na + and OH − intercalating anode and cathode. Despite the oxygen-evolving cathode, the battery exhibits high Coulombic efficiency because oxygen evolution is suppressed by asymmetric anode and cathode polarization. Together with the low voltage loss, the battery yields a high round-trip efficiency of 77.7% at 1 A g −1 . Other merits of this battery include moderate energy density and the use of safe, harmless, and cheap materials, manifesting a practical choice for grid energy storage. The ultra-fast intercalation reactions also endow the battery with high-rate performances comparable to supercapacitors. Moreover, this work proposes and verifies the concept of asymmetric electrode polarization, shifting the paradigm for electrode selection in aqueous batteries. • Aqueous alkaline dual-ion battery with Na + and OH − intercalation chemistry • Asymmetric anode and cathode polarization inhibits OER on cathode • The battery shows high Coulombic and round-trip efficiency • Battery-type charge-discharge curves and supercapacitor-type rate capability Xu et al. demonstrate an aqueous alkaline battery with Na + and OH − intercalation chemistry. The rapid and reversible reactions yield low voltage loss, while the asymmetric anode and cathode polarization inhibits the cathodic OER, altogether leading to high round-trip efficiency. The battery has a constant voltage but supercapacitor-type, high-power density.

Nanosilicate-Reinforced Silk Fibroin Hydrogel for Endogenous Regeneration of Both Cartilage and Subchondral Bone.

Osteochondral defects are characterized by injuries to both cartilage and subchondral bone, which is a result of trauma, inflammation, or inappropriate loading. Due to the unique biological properties of subchondral bone and cartilage, developing a tissue engineering scaffold that can promote dual-lineage regeneration of cartilage and bone simultaneously remains a great challenge. In this study, a microporous nanosilicate-reinforced enzymatically crosslinked silk fibroin (SF) hydrogel is fabricated by introducing montmorillonite (MMT) nanoparticles via intercalation chemistry. In vitro studies show that SF-MMT nanocomposite hydrogel has improved mechanical properties and hydrophilicity, as well as the bioactivities to promote the osteogenic differentiation of bone marrow mesenchymal stem cells and maintain chondrocyte phenotype compared with SF hydrogel. Global proteomic analysis verifies the dual-lineage bioactivities of SF-MMT nanocomposite hydrogel, which are probably regulated by multiple signaling pathways. Furthermore, it is observed that the biophysical interaction of cells and SF-MMT nanocomposite hydrogel is partially mediated by clathrin-mediated endocytosis and its downstream processes. In vivo, the SF-MMT nanocomposite hydrogel effectively promotes osteochondral regeneration as evidenced by macroscopic, micro-CT, and histological evaluation. In conclusion, a functionalized SF-MMT nanocomposite hydrogel is developed with dual-lineage bioactivity for osteochondral regeneration, indicating its potential in osteochondral tissue engineering.

(Digital Presentation) Design of High-Performance Antimony / MXene Hybrid Electrodes for Sodium-Ion Batteries

As a result of the growing electrification and the ever-increasing demand for batteries, scarcity of fossil resources of lithium, and the resulting rise in price, energy storage technologies beyond lithium aroused high interest throughout the past years.1-3 Sodium is a naturally abundant element in the earth and therefore offers the opportunity to develop a promising low-cost, large-scale energy application with favorable energy and power densities. Recently, frequent new and further developments on the anode and cathode materials for sodium-ion batteries have been made. In particular, the development of anode material presents massive challenge while several requirements of high capacity and long lifetime/high durability need to be fulfilled.The unique properties of the novel 2D material MXene, including their excellent electrical conductivity and accessible interlayer space, enable them to be used as attractive electrode materials for battery and supercapacitor. Still, a major drawback is that the capacity of Na+-ion storage by intercalation chemistry is limited due to the limited storage sites.4 As it comes to high-capacity materials, the research field of conversion and alloying materials provides highly attractive candidates. For example, antimony is a promising anode candidate, which undergoes alloying reaction with sodium to form Na3Sb, delivering a high theoretical capacity of 660 mAh g-1. Still, the major drawback of alloying materials is the high volume changes during sodiation and de-sodiation which often leads to electrode cracking, pulverization, continuous reformation of SEI and thus results in poor electrochemical performance. It is, therefore, highly promising to combine both, MXene and antimony for stable, high performance energy storage.Our work explores the best strategy to achieve Sb/MXene hybrid electrodes. There is a tremendous influence in the electrochemical performance dependent on Sb-to-MXene ratio, Sb distribution, and Sb/MXene entanglement. The optimized performance does not align with the highest amount of antimony, the smallest nanoparticles, or the largest interlayer distance of the MXene but by the most homogeneous distribution of antimony and MXene while both components remain electrochemically addressable. With the best optimized hybrid material, we obtained electrodes showing a specific capacity of 450 mAh g-1 at 0.1 A g-1 and 365 mAh g-1 at 4 A g-1, with capacity retention of around 96% after 100 cycles. References Perveen, T.; Siddiq, M.; Shahzad, N.; Ihsan, R.; Ahmad, A.; Shahzad, M. I., Prospects in anode materials for sodium ion batteries-A review. Renewable and Sustainable Energy Reviews 2020, 119, 109549.Skundin, A.; Kulova, T.; Yaroslavtsev, A., Sodium-ion batteries (a review). Russian Journal of Electrochemistry 2018, 54 (2), 113-152.Kundu, D.; Talaie, E.; Duffort, V.; Nazar, L. F., The emerging chemistry of sodium ion batteries for electrochemical energy storage. Angewandte Chemie International Edition 2015, 54 (11), 3431-3448.Kim, Y.; Ha, K. H.; Oh, S. M.; Lee, K. T., High‐capacity anode materials for sodium‐ion batteries. Chemistry–A European Journal 2014, 20 (38), 11980-11992. Figure: De-sodiation capacity and Coulombic efficiency versus cycle number of a simple mechanical mixed antimony MXene electrode (pink) and optimized hybrid material (blue). Figure 1

Tapping the True Potential of Carbon By Stabilized Li Plating: High Gravimetric / Areal Capacity Systems

With the advent of high-capacity lithium - sulfur chemistry, lithium – O2 system and the industrial impetus on increasing the areal loading of oxide-based cathode systems to improve the energy density of existing batteries, efficient and stable lithium plating/deplating in liquid electrolyte still remains the key for all these technologies to come into practical utilization or improve the existing commercial systems.The major electrochemical performance issues with lithium metal plating are poor coulombic efficiency of plating/deplating, the erratic voltage fluctuations which are reflected due to undesired plating morphology (high surface area lithium growth, mossy Li plating, dendritic lithium plating) and the decomposition of electrolyte on the growth sites (solid electrolyte interphase, SEI) during the plating process. The fundamental phenomena which dictate these issues are the electron transfer at the plating interface and the Li+ flux in the system. Subsequently, the reversibility of Li plating is determined by the stability of the deposition structure on the substrate along with that of solid electrolyte interface (SEI) upon repeated plating/deplating.Stabilization of lithium metal plating in liquid electrolyte is a critical barrier for high energy density and high-rate capability lithium-ion batteries. Carbon – based system with a high gravimetric capacity of 2500mAh/g – 3000mAh/g is developed surpassing intercalation chemistry by stabilizing the plating of lithium metal in liquid electrolytes to compete with that of silicon and graphite-based electrodes. Anode architecture utilizing carbon structures as the active material with the ability to control / restrict the Li plating sites as well as the morphology has been developed which improves the reversibility of the Li plating in the system.The innovative testing methodology developed reflects the true performance of the system with accuracy compared to the traditional coincell testing. The carbon-based nanostructured electrodes show a high theoretical capacity sustaining areal capacities of ~6mAh/cm2 for over 600 cycles with a high coulombic efficiency of ~99.75 – 99.94%. The system can sustain cathodes at areal capacity of 2 – 5 mAh/cm2 and areal current densities of 1mA/cm2 – 6mA/cm2 with good rate capability without sacrificing gravimetric capacity and energy density.A detailed testing protocol has been develped to distinguish the phenomenon of Li reaction and Li metal plating on the anode. A modified coin cell testing has been developed to control the Li plating to record accurate electrochemical signal. Results of these studies along with the electrode architecture, extensive electrochemical characterization including electrochemical impedance, rate capability and SEM analysis of the electrodes will be presented and discussed. Acknowledgement: The authors gratefully acknowledge the Department of Chemical and Petroleum Engineering, Energy Innovation Center, Nano Fabrication and Characterization Facility at University of Pittsburgh for their support.

(Invited) Nanotechnology for Industrial Electrochemical Energy Storage

Nanomaterials are expected to play important roles in the realization of our future society, expected to contribute to the realization of a sustainable society through ensuring smart materials to enable sustainability of water, air, and materials; and energy materials and devices to enable renewable energy production and energy saving. These have enormous industrial/commercial ramifications.Our society needs to mitigate or ideally reverse global climate change caused by anthropogenetic CO2 emissions resulting from our fossil-fuel-fed society. Electrification, which encourages and enables a circular society is an important part of the solution. It leads to urgent needs for new nanotechnologies and nanomaterials for improved solar cells, batteries, electrolyzers, and the fuel cell components that are needed to support a hydrogen economy. As a prime example, Li-ion batteries, for which the Nobel Prize was awarded in 2019, are the most popular rechargeable batteries today and have become the main power source not only for everyday needs such as portable electronic devices but also for larger-scale applications that will become indispensable society in the very near future.Although enormous effort has been devoted to improving the electrochemical performance of a large number of Li-based materials, today’s rechargeable batteries have energy densities that remain below theoretical values, and still have far-from-optimal longevity and safety. None of the current rechargeable batteries can meet all the challenging requirements for our energy-storage needs, so the race is on to develop next-generation Li-based systems that encapsulate the desired characteristics of high energy density, low cost, and improved safety. Success in this arena would have tremendous impact on a wide range of technologies ranging from EVs (land and marine), to drones, airplanes, robots, and grid-scale energy storage.The use of nanotechnology─which has progressed tremendously and continues to establish new ground─is vital to address the significant challenges that next-generation batteries present. These materials challenges remain whether the batteries operate on the basis of typical intercalation chemistry or conversion chemistry. Some of these challenges -as will be covered in this presentation - lie in the development of (a) nanomaterials that can withstand significant volume changes and bond rearrangements during conversion redox reactions, (b) nanocoatings that form protective layers on either the positive or negative electrode to stabilize the electrode–electrolyte interface at either high or low voltage, and (c) nanotechnologies to engineer solid–solid interfaces in all-solid-state batteries. Nanotechnology enables materials scientists to bring novel functions to all battery components that cannot be achieved by conventional approaches. This topic will be the central focus of this presentation.

Elastic Lattice Enabling Reversible Tetrahedral Li Storage Sites in a High-Capacity Manganese Oxide Cathode.

The key to breaking through the capacity limitation imposed by intercalation chemistry lies in the ability to harness more active sites that can reversibly accommodate more ions (e.g., Li+ ) and electrons within a finite space. However, excessive Li-ion insertion into the Li layer of layered cathodes results in fast performance decay due to the huge lattice change and irreversible phase transformation. In this study, an ultrahigh reversible capacity is demonstrated by a layered oxide cathode purely based on manganese. Through a wealth of characterizations, it is clarified that the presence of low-content Li2 MnO3 domains not only reduces the amount of irreversible O loss; but also regulates Mn migration in LiMnO2 domains, enabling elastic lattice with high reversibility for tetrahedral sites Li-ion storage in Li layers. This work utilizes bulk cation disorder to create stable Li-ion-storage tetrahedral sites and an elastic lattice for layered materials, with a reversible capacity of 600mA h g-1 , demonstrated in th range 0.6-4.9V versus Li/Li+ at 10mA g-1 . Admittedly, discharging to 0.6V might be too low for practical use, but this exploration is still of great importance as it conceptually demonstrates the limit of Li-ions insertion into layered oxide materials.

Layered Double Hydroxides for Sustainable Agriculture and Environment: An Overview.

Agricultural practices in modern society have a detrimental impact on the health of the ecosystem, environment, and consumers. The significantly high usage rate of chemicals causes serious harm, and the sector demands the development of innovative materials that can foster improved food production and lessen ecological impacts. The majority of layered double hydroxides (LDH) are synthetic. At the same time, some of them occur in the form of natural minerals (hydrotalcite), which have recently emerged as favorable materials and provided advanced and ingenious frontiers in various fields of agriculture through practical application possibilities that can replace conventional agricultural systems. LDH can exchange anions intercalated between the layers in the interlayer structure, and there is evidence that atmospheric carbon dioxide and moisture can completely break down LDH over time. Due to certain unique properties such as tunable structure, specific intercalation chemistry, pH-dependent stability, as well as retention of the guest molecules within interlayers and their subsequent controlled release, LDHs are increasingly investigated as materials to enhance yield, quality of crops, and soil in recent times. This review aims to present the current research progress in the design and development of LDH-based materials as nanoscale agrochemicals to illustrate its relevance in making agro-practices more sustainable and efficient. Specific emphasis is given to the functionality of these materials as effective materials for the slow release of fertilizers and plant growth factors as well as adsorption of toxic agrochemical residues and contaminants. Relevant research efforts have been briefly reviewed, and the potential of LDH as new generation green materials to provide solutions to agricultural problems for improving food productivity and security has been summarized.

Host-Guest Intercalation Chemistry for the Synthesis and Modification of Two-Dimensional Transition Metal Dichalcogenides.

Intercalation chemistry is of great importance in solid-state physics and chemistry for the ability to modulate electronic structures for constructing new materials with exotic properties. This ancient and versatile discipline has recently become prevailing in the synthesis and regulation of 2D transition metal dichalcogenides (TMDs) with atomic thickness due to diverse host-guest configurations and their impact on layered frameworks, which bring in extensive applications in electronics, optoelectronics, and other energy-based devices. In order to prepare 2D TMD materials with desired structure and properties, it is essential to gain in-depth understanding of the key role the intercalation chemistry plays in the preparation process. A focused review on recent advances regarding 2D TMD materials through intercalation exfoliation from the view of host, guest, and solvent interactions is provided. The effect of intercalation chemistry on TMD nanosheets synthesis and modification is comprehensively reviewed. The interactions between host and guest from the aspects of lattice strain, interlayer distance, and carrier density are considered. Finally, a prospectus of the future research opportunities for the intercalation chemistry of 2D materials is provided.

Cation and anion (de)intercalation into MXene/Perovskite oxides for high-rate intercalation pseudocapacitance

Intercalation pseudocapacitance is the next hope for electrochemical energy storage devices to offer high energy density without sacrificing power density. Under intercalation pseudocapacitance, ions (e.g. Li+ into T-Nb2O5, but not limited to cation intercalation only) intercalate into the host materials without phase conversions and no limitations from solid-state diffusion, unlike batteries. Here, a concept of both cations and anions (de)intercalation into the hybrid electrode comprising nanocomposite (MLMO) of MXene (Ti3C2Tx) and perovskite oxides (LaMnO3-δ, LMO) are demonstrated. Independently, multilayered MXene and oxygen deficient LMO show cation and anion-based intercalation pseudocapacitance, respectively. During analyzing the electrochemical process through ex situ XPS, it is observed that not only K+ ions but OH− ions also (via formation of O2−) (de)intercalate into MLMO and contribute to the total charge storage. Accordingly, MLMO exhibits high capacitance retention (70.82%) even at a high current density of 30 A g−1 (313.6 F g−1). Next, a fast-kinetics dual-ion intercalated pseudocapacitive symmetric device with 1.6 V is fabricated which shows a high energy density of 34.1 Wh kg−1 and astonishing power density of 14.51 kW kg−1. This study sheds light on new dual-ion intercalation chemistry and sets a concrete path for the establishment of high energy storage devices with fast-kinetics.

Recent Advances in Layered Metal-Oxide Cathodes for Application in Potassium-Ion Batteries.

To meet future energy demands, currently, dominant lithium‐ion batteries (LIBs) must be supported by abundant and cost‐effective alternative battery materials. Potassium‐ion batteries (KIBs) are promising alternatives to LIBs because KIB materials are abundant and because KIBs exhibit intercalation chemistry like LIBs and comparable energy densities. In pursuit of superior batteries, designing and developing highly efficient electrode materials are indispensable for meeting the requirements of large‐scale energy storage applications. Despite using graphite anodes in KIBs instead of in sodium‐ion batteries (NIBs), developing suitable KIB cathodes is extremely challenging and has attracted considerable research attention. Among the various cathode materials, layered metal oxides have attracted considerable interest owing to their tunable stoichiometry, high specific capacity, and structural stability. Therefore, the recent progress in layered metal‐oxide cathodes is comprehensively reviewed for application to KIBs and the fundamental material design, classification, phase transitions, preparation techniques, and corresponding electrochemical performance of KIBs are presented. Furthermore, the challenges and opportunities associated with developing layered oxide cathode materials are presented for practical application to KIBs.

Access to Ru(IV)–Ru(V) and Ru(V)–Ru(VI) Redox in Layered Li7RuO6 via Intercalation Reactions

The push to increase the capacity of oxides to store charge as Li-ion battery cathodes has challenged our knowledge of the boundaries of redox chemistry and its relationship to the atomic structure. Layered phases with Ru are now classical models in the quest for refined theories. Current understanding dictates that the highest formal state that can be reached in them is Ru(V), after which activity centered at the oxide anions is triggered. Yet, this picture is challenged by this investigation of the intercalation chemistry of Li7RuO6. Coupling structural and spectroscopic analysis with computational simulations, we show that Li7RuO6 is capable of highly reversible lithiation to Li8RuO6 through the Ru(V)/Ru(IV) redox couple. Li7RuO6 can also undergo anodic Li deintercalation, showing clear evidence of the reversible formation of Ru(VI) with octahedral coordination, an unusual state that is not accessible in other layered oxides. The results highlight the versatility of the Ru–O bond to undergo distinct redox transitions depending on the specific layered arrangements. They enrich our understanding of redox chemistry in solids while underscoring the need for descriptions of charge compensation that reflect the nuance of covalent interactions.

Antimicrobial alkali-activated slag through self-intercalation of benzoate in layered double hydroxides

Antimicrobial alkali-activated slag (AAS) with biocidal effectiveness is a promising cementitious binder for concrete infrastructure threatened by microbially induced concrete corrosion (MICC). In this work, the influence of sodium benzoate on the chemical reaction, phase assemblage, microstructure, and nanostructure of AAS was studied, with a particular focus on the potential in-situ formation of benzoate-intercalated layered double hydroxides (BZ-LDHs). In addition, the lattice structure, molecular bonds, and intercalation chemistry of pure BZ-LDHs synthesised using rehydration method were investigated. The results evidence the in-situ formation of BZ-LDHs in AAS incorporating sodium benzoate during alkaline activation. The benzoate anions are spontaneously intercalated in a bilayer manner in the interlayers of LDHs, with an average basal spacing of 1.568 nm. The incorporation of BZ slightly lowers the reaction degree of slag in AAS, but barely affects the composition and structure of calcium-aluminosilicate-hydrate (C-A-S-H) formed. The developed antimicrobial AAS with BZ-LDHs demonstrates remarkable bactericidal efficacy with a 95.0% effectiveness (when admixed with 3% BZ) in suppressing the growth of sulphur-oxidising bacteria Acidithiobacillus thiooxidans in this study.

Novel hybrid fatty solid material based on lambda-zirconium phosphate and omega-9 fatty acids: Synthesis and characterization

The preparation of a novel crystalline fatty lambda-zirconium phosphate oleate, λ- ZrPO4(OH)0.18(C18H33O2)0·82(CH3)2SO, is reported in this research work. The material is characterized and formulated on the basis of its elemental, TGA, FT-IR and X-ray analyses. The X-ray diffraction pattern reveals that the interlayer distance of our new fatty material is heavily increased (2.96 nm) in comparison with that of the pristine λ-ZrP (1.02 nm). Therefore, this material could have potential applications in the field of intercalation chemistry of large organic and inorganic guests.

Exploring the intercalation chemistry of layered yttrium hydroxides by 13C solid-state NMR spectroscopy

Layered rare earth hydroxides (LREHs) are a novel class of two-dimensional materials with potential applications in various fields. The exchange reactions with organic anions are typically the first step for the functionalization of LREHs. Although the laminar structures seem to be clear for anion-exchanged compounds, the state of intercalated organic anions and their interactions with cationic rare earth hydroxide layers remain unclear. Herein, we demonstrate that the use of 13C solid-state nuclear magnetic resonance (ssNMR) spectroscopy enables to extract key information on the state of intercalated organic anions such as their local chemical environment, stacking, and dynamics, which are often difficult or impossible to obtain previously. In combination with powder X-ray diffraction and ab initio density functional theory calculations, the intercalation chemistry of two representative layered yttrium hydroxides with selected monovalent organic anions was studied in detail. The products can undergo secondary exchange with a divalent organic anion, depending on the match between the basal spacing of two phases, i.e., the replacement of benzenesulfonate (BS−), 2,4-dimethylbenzene sulfonate (DMBS−), and 4-ethylbenzene sulfonate (EBS−) with 2,6-naphthalene disulfonate (NDS2−) is allowed due to the insignificant change in basal spacing after exchange, while the replacement of very long dodecyl benzene sulfonate (DBS−) and dodecyl sulfate (DS−) with NDS2− is forbidden. The results therefore provide valuable insights into the structure-property relationships of LREH-based functional materials.

Proton-Assisted Aqueous Manganese-Ion Battery Chemistry.

Aqueous manganese-ion batteries (MIBs) are promising energy storage systems because of the distinctive merits of Mn metal, in terms of high abundance, low cost, nontoxicity, high theoretical capacity and low redox potential. Conventional MIBs are based on the Mn2+ ion storage mechanism, whereas the capacity in cathode materials is generally limited due to the high charge density and large solvated ionic radius of Mn2+ ions in aqueous electrolytes. Herein, proton intercalation chemistry is introduced in aqueous MIBs, in which the layered Al0.1 V2 O5 ⋅1.5 H2 O (AlVO) cathode exhibits a consequent Mn2+ and H+ ion intercalation/extraction process. Such an energy storage mechanism contributes to enhanced electrochemical performance, including high capacity, fast reaction kinetics and stable cycling behavior. Benefiting from this proton intercalation chemistry, the aqueous Mn||AlVO cells could deliver high specific energy and power simultaneously. This work provides a route for the design of high-performance aqueous MIBs.

Proton‐Assisted Aqueous Manganese‐Ion Battery Chemistry

AbstractAqueous manganese‐ion batteries (MIBs) are promising energy storage systems because of the distinctive merits of Mn metal, in terms of high abundance, low cost, nontoxicity, high theoretical capacity and low redox potential. Conventional MIBs are based on the Mn2+ ion storage mechanism, whereas the capacity in cathode materials is generally limited due to the high charge density and large solvated ionic radius of Mn2+ ions in aqueous electrolytes. Herein, proton intercalation chemistry is introduced in aqueous MIBs, in which the layered Al0.1V2O5⋅1.5 H2O (AlVO) cathode exhibits a consequent Mn2+ and H+ ion intercalation/extraction process. Such an energy storage mechanism contributes to enhanced electrochemical performance, including high capacity, fast reaction kinetics and stable cycling behavior. Benefiting from this proton intercalation chemistry, the aqueous Mn||AlVO cells could deliver high specific energy and power simultaneously. This work provides a route for the design of high‐performance aqueous MIBs.

Mechanistic Insights into the Interplay between Ion Intercalation and Water Electrolysis in Aqueous Batteries.

Improving electrolyte stability to suppress water electrolysis represents a basic principle for designing aqueous batteries. Herein, we investigate counterintuitive roles that water electrolysis plays in regulating intercalation chemistry. Using the NaxFe[Fe(CN)6]∥NaTi2(PO4)3 (x < 1) aqueous battery as a platform, we report that high-voltage overcharging can serve as an electrochemical activation approach to achieving concurrent Na-ion intercalation and an electrolytic oxygen evolution reaction. When the cell capacity is intrinsically limited by deficient cyclable Na ions, the electrolytic water oxidation on the cathode allows for extra Na-ion intercalation from the electrolyte to the NaTi2(PO4)3 anode, leading to a major increase in cyclable Na ions and specific capacity. The parasitic oxygen generation and potential transition-metal dissolution, as proved by our synchrotron and imaging tools, can be significantly mitigated with a simple reassembling approach, which enables stable electrochemical performance and sheds light on manipulating ion intercalation and water electrolysis for battery fast charging and recycling.