Ion Batteries Research Articles

Rational design of MXene-MoS2 heterostructure with rapid ion transport rate as an advanced anode for sodium-ion batteries

Molybdenum disulfide (MoS2) has attracted great attention as a promising material for sodium (Na)-ion batteries (SIBs) due to its high theoretical capacity and unique layered structure. However, the intrinsic poor electrical conductivity and uncontrollable volume change of the pristine MoS2 during the ion insertion/extraction process result in its low rate performance and rapid capacity fading. Considering that the migration path length of the ion determines its diffusion time, shortening it can further increase the diffusion rate, thereby realizing fast Na ion storage. Herein, we prepare an interconnected network heterostructure consisting of small-sized MoS2 anchored on nitrogen-doped MXene substrates (MXene-MoS2). The as-prepared MXene-MoS2 heterostructure not only enhances the electrical conductivity and structural stability of the electrode materials but also reduces the Na ion diffusion length to achieve rapid Na ion transport kinetics. Meanwhile, the robust heterointerface guarantees fast and unimpeded electron transfer channels, thereby improving the electrochemical reaction kinetics. As a consequence, the MXene-MoS2 delivers an excellent reversible capacity of 315 mAh g−1 at 0.2 A g−1 and 220.0 mAh g−1 after 1000 cycles at 2.0 A g−1. This study may provide the possibility for the practical application of the MXene-MoS2 as a SIB anode.

Optimized crystal orientation for enhanced reaction kinetics and reversibility of SnSe/NC hollow nanospheres towards high-rate and long-term lithium/sodium storage.

The development of anode materials with high theoretical capacity and cycling stability is very important for the electrochemical performance of lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Herein, SnSe/NC hollow nanospheres with different crystal orientations were prepared by regulating the high-temperature selenization of the PDA@SnO2 precursor for lithium/sodium storage. In SnSe/NC hollow nanospheres, the physical buffering and chemical bonding of the nitrogen carbon matrix and SnSe nanoparticles could inhibit volume expansion and polyselenide loss, thus maintaining long-term structural stability. More importantly, electrochemical tests and DFT calculations show that the diffusion energy barrier of Li+/Na+ is significantly reduced at the SnSe (400) rather than the usual (111) facet, which is conducive to the uniformity of ion insertion into SnSe, thus effectively enhancing the reaction kinetics and reversibility of lithium/sodium storage. Therefore, SnSe/NC hollow nanospheres with rich SnSe (400) and good dispersion formed at 550 °C delivered the best reversible specific capacity and rate performance. After a long period of 900 cycles, the capacity retention of lithium/sodium ion batteries is close to 84.88% and 77.05%, respectively. Our findings provide valuable insights into the design of metal selenides for advanced LIBs/SIBs.

Nitrogen self-doped porous carbon based on sunflower seed hulls as excellent double anodes for potassium/sodium ion batteries

Nitrogen self-doped porous carbon based on sunflower seed hulls as excellent double anodes for potassium/sodium ion batteries

First-principles calculations of monolayered Al2Te5: a promising 2D donor semiconductor with ultrahigh visible light harvesting.

Atomically thin two-dimensional (2D) crystals have piqued the curiosity of researchers due to their unique features and potential applications, such as catalysis and ion batteries. One essential and desirable aspect of 2D materials is that they have a large photoreactive contact surface for optical absorption. Here, a 2D crystal is proposed that possesses a moderate adjustable indirect band gap of 1.95 eV (HSE06) and exhibits ultrahigh visible light harvesting with a absorption coefficient of up to 108 cm-1 in the ∼380 to 800 nm range of the visible light spectrum. Besides that, the indirect band gap can be converted to a direct one under biaxial strain. By means of density functional theory, the 2D Al2Te5 monolayer displays great stability and promise of experimental fabrication. These advantages will provide considerable application potential for future photovoltaics (PV) devices.

Unravelling and quantifying the aging processes of commercial Li(Ni0.5Co0.2Mn0.3)O2/graphite lithium-ion batteries under constant current cycling

Constant current charging and discharging is widely used nowadays for commercial lithium (Li) ion batteries (LIBs) in applications of portable electronic devices and electric vehicles.

Vanadium fluorophosphates: advanced cathode materials for next-generation secondary batteries.

Next-generation secondary batteries including sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) are considered the most promising candidates for application to large-scale energy storage systems due to their abundant, evenly distributed and cost-effective sodium/potassium raw materials. The electrochemical performance of SIBs (PIBs) significantly depends on the inherent characteristics of the cathode material. Among the wide variety of cathode materials, sodium/potassium vanadium fluorophosphate (denoted as MVPF, M = Na and K) composites are widely investigated due to their fast ion transportation and robust structure. However, their poor electron conductivity leads to low specific capacity and poor rate capacity, limiting the further application of MVPF cathodes in large-scale energy storage. Accordingly, several modification strategies have been proposed to improve the performance of MVPF such as conductive coating, morphological regulation, and heteroatomic doping, which boost the electronic conductivity of these cathodes and enhance Na (K) ion transportation. Furthermore, the development and application of MVPF cathodes in SIBs at low temperatures are also outlined. Finally, we present a brief summary of the remaining challenges and corresponding strategies for the future development of MVPF cathodes.

Functionalized two-dimensional iron boride compounds as novel electrode materials in Li-ion batteries.

MBenes, a class of two-dimensional metal borides, have emerged as a cutting-edge research frontier and a hotspot for electrode materials in ion batteries. This work presents a systematic investigation of the performance of two-dimensional iron boride (FeB) as an electrode material for lithium-ion batteries (LIBs), utilizing first-principles calculations. The results indicate that FeB exhibits remarkable structural stability and excellent conductivity, making it an extremely promising electrode material for LIBs. FeB has the capability to adsorb a monolayer of Li atoms, and exhibits a maximum theoretical capacity of 364 mA h g-1, a high average open circuit voltage (OCV) of 1.08 V, and a low diffusion barrier energy of 0.24 eV. Through the investigation of electrochemical properties of functionalized FeB, it has been discovered that surface functionalization exerts a positive impact on lithium storage. Theoretical lithium storage capacities of FeBT (T = F, O and S) are 538 mA h g-1, 555 mA h g-1 and 476 mA h g-1, respectively. However, the introduction of F and O functional groups significantly reduces diffusion barriers to 0.081 eV and 0.036 eV, respectively, while the introduction of the S functional group markedly decreases the average OCV to approximately 0.25 V. These interesting findings suggest that FeB has great potential in the future development of LIBs.

Enhancing organic cathodes of aqueous zinc-ion batteries via utilizing steric hindrance and electron cloud equalization.

Polyaniline (PANI), with merits of high electronic conductivity and capacity, is a promising material for zinc (Zn)-ion batteries. However, its redox window in Zn batteries is often limited, mainly due to the oxidative degradation at high potentials-in which imine groups can be attacked by water molecules. Here, we introduce phytic acid, a kind of supermolecule acid radical ion, as a dopant and electrolyte additive. Various in/ex situ analyses and theoretical calculations prove that the steric hindrance effect can prevent electroactive sites from the attack by water molecules. Meanwhile, the redox reaction can be stabilized by an even distribution of electron cloud due to the conjugated structure of phenazine groups. Accordingly, the assembled Zn-PANI battery can allow stable and long-term charge-discharge reactions to occur at a potential as high as 2.0 V with a discharged plateau of 1.5 V, and it also shows high rate performance and stable long cycle life (75% capacity retention after 1000 cycles at 10 A g-1).

Synthesis and Studies on Polymer Electrolyte Membrane using Polyvinyl Alcohol, Polyvinylidene Fluoride and Ammonium Bromide as Dopants for Proton-conducting Electrolyte

Different compositions of Polyvinyl alcohol (PVA), Polyvinylidene fluoride (PVDF) and Ammonium bromide (NH4Br) were employed to synthesize the proton-conducting polymer electrolyte membranes by Solution casting method, which have potential applications in proton (H+) ion batteries and fuel cells. Structural, vibrational and electrical properties of the synthesized polymer electrolyte membrane were characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy and Electrical Impedance Spectroscopy (EIS) analysis and results were reported. The semi-crystalline nature of the prepared polymer was confirmed by XRD analysis. FTIR spectroscopy revealed the vibrational spectra of the prepared polymer membrane. The Nyquist plot drawn from the AC Impedance analysis was a straight line, confirming the dielectric nature of the prepared membrane.

A Symmetric Aqueous Magnesium Ion Supercapattery Based on Covalent Organic Frameworks

AbstractAqueous magnesium ion‐based batteries have attracted significant research interest due to the two‐electron transfer process, small cation radius, low reduction potential as well as the inert hydrogen evolution reaction. However, the high surface charge density of divalent Mg2+ ions results in sluggish solid‐state diffusion kinetics, which significantly limits the number of host materials suitable for effective Mg2+ ion storage. Here, for the first time, covalent organic frameworks (COFs) are explored as host materials for high‐rate aqueous Mg2+ ion batteries. Combining electrochemical and spectral characterization with theoretical simulation, a synergistic charge storage mechanism involving the reaction of nitrogen and oxygen bridged by Mg2+ ions is revealed. Using electrochemical analysis, it is shown that the Mg2+ ion diffusion kinetics are dominated by the surface pseudocapacitive behavior in COFs, which achieves a favorable rate performance and durable cyclic stability. This work offers a new perspective on the storage of Mg2+ ions in COF host materials.

The Critical Significance of Boron Mine in Future Energy Technologies

The boron element forms more than 600 compounds with different element roots and shows very different properties. Boron compounds with these different properties deserve to be the most crucial strategic feature in the world as they meet the demands above the targeted standards in industries such as energy, structure, chemistry, weapons, and space. Today, the industries of developed countries have begun to take advantage of these energy sources due to the reduction of fossil energy resources, the inability of the industry to store enough electricity for an entire facility, and the limitations imposed on environmental policies. Developing countries continue to use fossil resources, but health and environmental costs are increasing. Whether they are developed or developing countries, they have attached importance to the research of energy systems that can replace fossil energy systems, which are environmentally friendly, sustainable, and high-performance. Boron has an essential role in the energy field for the isolation, high energy value retention, fuel and ion batteries, solar panels, and high-temperature transistors. In this study, the desired properties of boron compounds in energy studies were investigated by considering the positive effects of boron on the energy demand.

Templated Synthesis of SiO2 Nanotubes for Lithium-Ion Battery Applications: An In Situ (Scanning) Transmission Electron Microscopy Study.

One of the weaknesses of silicon-based batteries is the rapid deterioration of the charge-storage capacity with increasing cycle numbers. Pure silicon anodes tend to suffer from poor cycling ability due to the pulverization of the crystal structure after repeated charge and discharge cycles. In this work, we present the synthesis of a hollow nanostructured SiO2 material for lithium-ion anode applications to counter this drawback. To improve the understanding of the synthesis route, the crucial synthesis step of removing the ZnO template core is shown using an in situ closed gas-cell sample holder for transmission electron microscopy. A direct visual observation of the removal of the ZnO template from the SiO2 shell is yet to be reported in the literature and is a critical step in understanding the mechanism by which these hollow nanostructures form from their core-shell precursors for future electrode material design. Using this unique technique, observation of dynamic phenomena at the individual particle scale is possible with simultaneous heating in a reactive gas environment. The electrochemical benefits of the hollow morphology are demonstrated with exceptional cycling performance, with capacity increasing with subsequent charge-discharge cycles. This demonstrates the criticality of nanostructured battery materials for the development of next-generation Li+-ion batteries.

S/N-co-doped graphite nanosheets exfoliated via three-roll milling for high-performance sodium/potassium ion batteries

Due to its larger ionic radius, further studies are needed before graphite can be used as an anode for sodium/potassium-ion batteries (SIBs/KIBs). It is believed that doping and increasing the layer spacing can improve the Na+/K+ storage. Herein, S/N co-doped graphite nanosheets (GNS) with an enlarged interlayer spacing of 0.39 nm were prepared via exfoliation with three-roll milling (TRM) combined with thiourea heated at different temperatures. This method generates abundant defects and active sites for GNS, as well as facilitates rapid access and transport of electrolytes and electrons/ions. The electrochemical results show that the S/N-doped GNS exfoliated 15 times and heated at 600 °C (SNGNS15-600) with thiourea as the electrode delivers a discharge capacity of 94 mAh g–1 over 6000 cycles at 10 A g–1 with an enhanced rate capability and stable performance for application in SIBs. Calculations using density functional theory show that the increased interlayer spacing by TRM and S, N co-doping enhances the adsorption energies of Na+ on graphite, thus improving the Na+ storage. As the anode for KIBs, the SNGNS15-600 electrode has a capacity of 142 mAh g–1 after 5000 cycles at 0.5 A g–1. This study provides an essential theoretical basis for the effective exfoliation of layered graphite-based materials and their applications in energy storage.

Layer-stacking of chalcogenide-terminated MXenes Ti2CT2(T = O, S, Se, Te) and their applications in metal-ion batteries

Owning to limited supply of lithium for Li-ion batteries, the development of non-Li-ion batteries (such as Na+, K+ Mg2+, Ca2+, and Al3+ ion batteries) has attracted significant research interest. In this work, by means of the first-principles calculations, we systematically investigated the performance of chalcogenide-terminated MXenes Ti2CT2 (T = O, S, Se, and Te) as electrodes for Li-ion and non-Li-ion batteries, as well as the layer-stacking and electronic properties of Ti2CT2. We find that the stacking type of O and Te terminated Ti2C multilayers with AA stacking differs from that of S and Se terminated Ti2C multilayers with AB stacking. More importantly, Ti2CO2 monolayer can be potential anode material for Na- and K-ion batteries with high capacities and very low diffusion barriers (0.03–0.11 eV), while Ti2CS2 and Ti2CSe2 are promising anode materials with relatively low average open circuit voltages (OCVs) for Na-, K-, and Ca-ion batteries (0.4–0.87 V). Among these materials, Ti2CS2 exhibits the largest ion capacity of 616 mAh g−1. These results of our work may inspire further studies of Ti2C-MXenes multilayers as electrodes for metal-ion batteries either experimentally or theoretically.

What is limiting the potential window in aqueous sodium‐ion batteries? Online study of the hydrogen‐, oxygen‐ and CO2‐evolution reactions at NaTi2(PO4)3 and Na0.44MnO2 electrodes

AbstractNaTi2(PO4)3 (NTP) and Na0.44MnO2 (NMO), and their derivatives, have emerged as the most promising materials for aqueous Na‐ion batteries. For both, NTP and NMO, avoiding the evolution of hydrogen and oxygen is found to be mandatory in order to mitigate material dissolution. Intriguingly, however, no direct determination of the hydrogen and oxygen evolution reactions (HER and OER) has yet been carried out. Using differential electrochemical mass spectrometry (DEMS) we directly identify the onset potentials for the HER and OER. Surprisingly, the potential window is found to be significantly smaller than suggested by commonly employed cyclic voltammetry measurements. CO2 evolution, upon decomposition of carbon black, is observed at an onset potential of 1.61 VRHE, which is 0.25 V more cathodic than the OER for the NMO electrode. Our results show that the state‐of‐the‐art carbon additive plays a crucial role in the stability of the positive NMO electrode in the ion battery.

Thermodynamics of Vacuum Chloride Volatilization of Ni, Co, Mn, Li, Al, and Cu in Spent Lithium−Ion Battery

In recent years the chlorination leaching separation process in the field of hydrometallurgy has been developed considerably. However, the development of the chlorination separation process in the field of pyrometallurgy has lagged. In this paper, the thermodynamics of vacuum chlorination volatilization of valuable metals Ni, Co, Mn, Li, Al, and Cu from spent lithium−ion batteries is investigated, and it is found that chlorination helps to achieve the trapping and separation of the singlet metals. With the help of Factsage 8.1, a theoretical map of the stable regions of valuable metal chlorides, the order of separation of each chloride at 10 Pa, and a discussion of the behavior of excess CuCl2 in the system at different temperatures were determined. This paper provides research ideas in the fields of selective separation of alloying elements in the carbothermal reduction products of waste lithium−ion batteries and one−step separation of valuable metals by carbothermal reduction.

First-principles study of ZIF-8 as anode for Na and K ion batteries

Zeolitic imidazolate frameworks (ZIFs) have been investigated experimentally as anodes for Na and K ion batteries. In this work, atomic ZIF-8 models with Zn vacancies have been constructed and the adsorption and diffusion properties of alkali metal atoms are analyzed by density functional theory (DFT) calculations. Zinc vacancies have strong adsorption energy for alkali metal atoms, especially when the first atom is inserted. Additionally, the intercalation of alkali metal atoms would reduce energy band gap of ZIF-8 from 4.85 eV to 4.31 eV for Na and 3.82 eV for K. Moreover, alkali metal atoms can diffuse smoothly in ZIF-8, and the energy barriers are 0.10 eV for Li, 0.45 eV for Na and 0.66 eV for K, respectively. This work deeply explores the interaction mechanism between alkali metals and ZIF-8 theoretically, and provides a reference for the future design of porous carbon materials as anodes for metal ion batteries.

Emerging 2D Copper-Based Materials for Energy Storage and Conversion: A Review and Perspective.

2D materials have shown great potential as electrode materials that determine the performance of a range of electrochemical energy technologies. Among these, 2D copper-based materials, such as Cu-O, Cu-S, Cu-Se, Cu-N, and Cu-P, have attracted tremendous research interest, because of the combination of remarkable properties, such as low cost, excellent chemical stability, facile fabrication, and significant electrochemical properties. Herein, the recent advances in the emerging 2D copper-based materials are summarized. A brief summary of the crystal structures and synthetic methods is started, and innovative strategies for improving electrochemical performances of 2D copper-based materials are described in detail through defect engineering, heterostructure construction, and surface functionalization. Furthermore, their state-of-the-art applications in electrochemical energy storage including supercapacitors (SCs), alkali (Li, Na, and K)-ion batteries, multivalent metal (Mg and Al)-ion batteries, and hybrid Mg/Li-ion batteries are described. In addition, the electrocatalysis applications of 2D copper-based materials in metal-air batteries, water-splitting, and CO2 reduction reaction (CO2 RR) are also discussed. This review also discusses the charge storage mechanisms of 2D copper-based materials by various advanced characterization techniques. The review with a perspective of the current challenges and research outlook of such 2D copper-based materials for high-performance energy storage and conversion applications is concluded.

A Novel Hierarchical Structure of SnCu2Se4/d-Ti3C2Tx/NPC for a Lithium/Sodium Ion Battery and Hybrid Capacitor with Long-Term Cycling Stabilities

To alleviate kinetics imbalance and capacity insufficiency simultaneously, a novel hierarchical structure (SnCu2Se4/d-Ti3C2Tx/NPC) composed of delaminated Ti3C2Tx, SnCu2Se4 nanoparticles, and N-doped porous carbon layers is designed as a battery-type anode for lithium/sodium ion hybrid capacitor (LIC/SIC). The combination of SnCu2Se4 nanoparticles with high specific capacity, d-Ti3C2Tx with accelerated ion diffusion path, and NPC with enhanced electronic conductivity makes the SnCu2Se4/d-Ti3C2Tx/NPC composite possess excellent cycling stabilities in half-cell lithium-ion and sodium-ion batteries (LIB and SIB), with capacities of 114 mAh g-1 after 6000 cycles at 10 A g-1 for LIB and 296 mAh g-1 after 900 cycles at 1.0 A g-1 for SIB. The rate performance is also outstanding, with recovered capacity of 738 mAh g-1 at 0.1 A g-1 after cycles at current densities up to 50 A g-1 for LIB. Subsequently, LIC and SIC based on the SnCu2Se4/d-Ti3C2Tx/NPC anode and activated carbon cathode exhibit high energy densities of 147.9 and 158.6 Wh kg-1 at a power density of 100 W kg-1, respectively. They also possess distinctive long lifespans with capacity retentions of 78 and 81% after 10,000 cycles at 1.0 A g-1, respectively, demonstrating the feasibility of SnCu2Se4/d-Ti3C2Tx/NPC toward energy devices requiring high energy density, power density, and long-term stability.

Anode/Cathode Dual‐Purpose Aluminum Current Collectors for Aqueous Zinc‐Ion Batteries

AbstractRechargeable aqueous zinc (Zn)‐ion batteries (RAZIBs), which use non‐flammable aqueous electrolytes and low‐cost electrode materials, show great potential to boost the development of safe, cost‐effective, and highly efficient energy storage systems. The adoption of lightweight and inexpensive aluminum (Al) as current collectors seems to be a good vision, but Al exhibits an easily‐corroded nature and a high impedance in aqueous electrolytes, making it a challenge to realize the utilization of Al current collector in RAZIBs. In this study, through the direct current magnetron sputtering, niobium (Nb) coated Al (Al‐Nb) foils are prepared, which shows superior corrosion‐resistance in an aqueous solution, while maintaining a satisfying electronic conductivity. Moreover, the Al‐Nb foils can be adopted to both anode and cathode current collectors while exhibiting high coulombic efficiency and good cycling stability even when they are tested under a condition that can meet the real‐world application demands, e.g., the Zn||Al‐Nb half‐cell shows an average coulombic efficiency of 99.17% in 320 cycles under a current density of 25 mA cm−2 and a galvanizing capacity of 6.25 mAh cm−2. The superior performance of the modified Al current collectors may mark a significant step toward the development of high‐energy‐density aqueous batteries.