Metal-ion Batteries Research Articles

Chemo-Mechanics of Alkali-Ion Intercalation into Iron Phosphate Composite Cathodes

Development of cathode structures suitable for Na-ion and K-ion batteries is still one of the major challenges on the way to the design of next-generation alkali metal-ion batteries. Although Li, Na and K belong to the same alkali metal group with a single charge in their cation form, intercalation of Na+ and K+ ions in electrodes is difficult since ionic radii of Na+ (0.98 Å) and K+ (1.38 Å) are larger than that of Li+ (0.69Å). Therefore, physical, and electrochemical behavior of the cathode materials in response to Na+ and K+ ion intercalation is expected to be fundamentally different than the response to Li+ ion. However, there is not much known about how electrochemical reactions and transport of ions take place in cathode materials with different alkali metal ions. There have been several studies focusing on electrochemical characterization and investigation of the structural changes in the electrode materials. Lack of insight into these reaction-transport mechanisms limits the design of novel cathode materials for Na-ion and K-ion batteries. Comparative studies between Li-ion, Na-ion and K-ion battery cathodes are critical to identify fundamental similarities and differences during intercalation. Even modest expansions in brittle cathodes can cause particle fracturing in a larger crystalline-size scale. Intercalation of larger ions can cause structural collapse and amorphization induced by continuous strains and distortions. Although the amorphization in the structure can be easily identified by conventional diffraction or electron microscopy techniques, quantitative analysis of the physical changes in the structure during and after amorphization while cycling the battery electrode is critical.In the first part of the talk, we will first report the utilization of in situ digital image correlation and in-operando X-ray diffraction (XRD) techniques to probe dynamic changes in the amorphous phase of iron phosphate during potassium intercalation. A new experimental approach allows to monitor dynamic physical and structural changes in the amorphous phase of the electrodes. In-operando XRD demonstrates amorphization in the electrode’s nanostructure during the first charge / discharge cycle. In situ strain analysis detects the reversible deformations associated with redox reactions in the amorphous phases. This method offers new insights to study mechanics of ion intercalation in the amorphous nanostructures.In the second part of the talk, we will compare the electrochemical and mechanical response of the iron phosphate cathodes upon Li, Na and K ion intercalation by using electrochemical techniques and in situ digital image correlation. Iron phosphate model electrodes were prepared by electrochemical displacement technique in order to ensure identical morphology, structure and chemistry in the pristine iron phosphate electrodes. Strain evolution during Li and Na intercalation results in more linear dependence on the state of charge / discharge except the first discharge of NaFePO4. However, strains generated in the electrode shows nonlinear behavior during insertion / extraction of K ions. Interestingly, when the same amount of K and Na ions are intercalated, similar chemomechanical expansions were observed. However, strain rate calculations showed that K ion intercalation results in a progressive increase in the strain rate, whereas Li and Na intercalation induce nearly constant strain rates. Potential-dependent behaviors also demonstrate more sluggish redox reactions during K intercalation, compared to the Li and Na intercalation. These observations provide a fundamental insight into the impact of alkali ions on the redox chemistry and associated chemomechanical deformations.

Ultrafast synthesis of hard carbon anodes for sodium-ion batteries.

Hard carbons (HCs) are a significantly promising anode material for alkali metal-ion batteries. However, long calcination time and much energy consumption are required for the traditional fabrication way, resulting in an obstacle for high-throughput synthesis and structure regulation of HCs. Herein, we report an emerging sintering method to rapidly fabricate HCs from different carbon precursors at an ultrafast heating rate (300 to 500 °C min-1) under one minute by a multifield-regulated spark plasma sintering (SPS) technology. HCs prepared via the SPS possess significantly fewer defects, lower porosity, and less oxygen content than those pyrolyzed in traditional sintering ways. The molecular dynamics simulations are employed to elucidate the mechanism of the remarkably accelerated pyrolysis from the quickly increased carbon sp2 content under the multifield effect. As a proof of concept, the SPS-derived HC exhibits an improved initial Coulombic efficiency (88.9%), a larger reversible capacity (299.4 mAh⋅g-1), and remarkably enhanced rate capacities (136.6 mAh⋅g-1 at 5 A⋅g-1) than anode materials derived from a traditional route for Na-ion batteries.

Electronic and magnetic properties in nitrogen-doped 2D titanium carbides (MXenes): Insight from first-principles calculations

First-principles computations were performed to investigate the electronic and magnetic properties of pristine and nitrogen (N)-doped Ti2C and Ti3C2 MXenes. The effects of the concentrations and the distributions of nitrogen were considered. Our results show that N doping can enhance the conductivity of Ti2C and Ti3C2 MXenes, which both present metallic character under different N concentration. The metallicity of N-doped Ti2C and Ti3C2 MXenes indicates potential in metal-ion batteries. Also, N doping leads to an antiferromagnetic (AFM)-ferromagnetic (FM) transition for Ti3C2. The critical concentration from AFM to FM configurations is between 25% and 50%. Importantly, the magnetic state of the N-doped Ti3C2 monolayers is related with the N distribution. However, Ti2C systems maintain an AFM state regardless of N concentrations or N distributions. Thus, based on the basic understanding of the N-doped Ti2C and Ti3C2 monolayer, we believe that our findings would provide theoretical support for the multifaceted application of the C-based MXenes.

A review of π-conjugated polymer-based nanocomposites for metal-ion batteries and supercapacitors.

Owing to their extraordinary properties of π-conjugated polymers (π-CPs), such as light weight, structural versatility, ease of synthesis and environmentally friendly nature, they have attracted considerable attention as electrode material for metal-ion batteries (MIBs) and supercapacitors (SCPs). Recently, researchers have focused on developing nanostructured π-CPs and their composites with metal oxides and carbon-based materials to enhance the energy density and capacitive performance of MIBs and SCPs. Also, the researchers recently demonstrated various novel strategies to combine high electrical conductivity and high redox activity of different π-CPs. To reflect this fact, the present review investigates the current advancements in the synthesis of nanostructured π-CPs and their composites. Further, this review explores the recent development in different methods for the fabrication and design of π-CPs electrodes for MIBs and SCPs. In review, finally, the future prospects and challenges of π-CPs as an electrode materials for strategies for MIBs and SCPs are also presented.

The mystery and promise of multivalent metal-ion batteries

Despite mounting interest and extensive research efforts in developing multivalent (MV) metal-ion battery chemistries (Zn2+, Mg2+, Ca2+, Al3+, etc.), the commercial prospects for these energy storage systems are still obfuscated by fundamental scientific questions and engineering challenges. In particular, the charge storage mechanism(s) of the positive electrode and the implications on achievable electrode and full cell-level performance remain intensely debated topics in the field. In this minireview, we highlight some of the recent progress and uncertainty in elucidating capacity contributions and accompanying mechanisms for different charge carriers (H+, MV-ion, structural ion, anion, and charged solvates/complexes). We then present cell balancing and increasing metal anode utilization as major remaining challenges and propose design strategies and future directions for realizing practical MV metal-ion batteries.

Frontispiece: Progress and Perspectives on Covalent‐Organic Frameworks (COFs) and Composites for Various Energy Applications

Covalent-organic frameworks: This review represents the progress made on the design principles and synthetic strategies for the construction of COFs and their composites for various energy applications such as different types of metal-ion batteries (MIBs), supercapacitors, water splitting (hydrogen evolution reaction, HER and oxygen evolution reaction, OER) and solar cells. Attempts have been made to correlate the structural and mechanistic characteristics of COFs with their applications. An understanding is developed of various strategies to tailor their performance towards desired applications, which will shed light on some possible modification aspects of COF structures with various conducting additives to greatly boost their properties. For more information, see the Review by S.M. Mobin et al. on page 13669.

Promising two-dimensional T-silicene as high capacity anode for rechargeable lithium-ion and sodium-ion batteries

In recent years, various high-performance electrode materials of alkali metal ion batteries have emerged one after another. Here, for the first time, we used first-principles to explore the possibility of using T-silicene as an anode material in lithium-ion batteries (LIBs) and sodium-ion batteries (NIBs). Firstly, we identified T-silicene is thermally stable at 300 K, then calculated and compared the interaction of Li/Na ions on T-silicene, also gradually increased the ions concentration until the full saturation of the surfaces is achieved. Our research demonstrates that not only the T-silicene lattice change of the configuration is 2.59%/1.21% for Li/Na, which are much lower than other 2D silicene, but also average open-circuit voltage is low as 0.173/0.192 V for Li/Na. Additionally, T-silicene has suitable storage capacity, good electric conductivity, and a low diffusion barrier. As has been stated, our results contribute to the potential application of T-silicene for LIBs/NIBs.

Diradicals or Zwitterions: The Chemical States of m -Benzoquinone and Structural Variation after Storage of Li Ions

Diradicals or Zwitterions: The Chemical States of <i>m</i> -Benzoquinone and Structural Variation after Storage of Li Ions

Growth Mechanism of Micro/Nano Metal Dendrites and Cumulative Strategies for Countering Its Impacts in Metal Ion Batteries: A Review.

Metal-ion batteries are capable of delivering high energy density with a longer lifespan. However, they are subject to several issues limiting their utilization. One critical impediment is the budding and extension of solid protuberances on the anodic surface, which hinders the cell functionalities. These protuberances expand continuously during the cyclic processes, extending through the separator sheath and leading to electrical shorting. The progression of a protrusion relies on a number of in situ and ex situ factors that can be evaluated theoretically through modeling or via laboratory experimentation. However, it is essential to identify the dynamics and mechanism of protrusion outgrowth. This review article explores recent advances in alleviating metal dendrites in battery systems, specifically alkali metals. In detail, we address the challenges associated with battery breakdown, including the underlying mechanism of dendrite generation and swelling. We discuss the feasible solutions to mitigate the dendrites, as well as their pros and cons, highlighting future research directions. It is of great importance to analyze dendrite suppression within a pragmatic framework with synergy in order to discover a unique solution to ensure the viability of present (Li) and future-generation batteries (Na and K) for commercial use.

Hierarchical CoNi-LDH nanosheet array with hydrogen vacancy for high-performance aqueous battery cathode

Aqueous rechargeable multiple metal-ion storage battery (ARSB) has a large potential in energy storage devices due to their safe usage, low cost and high rate capability. Nevertheless, the performance of practical ARSB is largely restricted by low capacity and limited cathode materials. Herein, we demonstrate an efficient cathode material based on CoNi-layered double hydroxide (LDH) nanosheets arrays with abundant hydrogen vacancy induced by electrochemical activation process for high performance of cations storage. Consequently, the electrochemical activated CoNi-LDH (ECA-CoNi-LDH) nanosheets arrays exhibit high metal ion (Li+, Na+, Zn2+, Mg2+ and Ca2+) storage capacities, which is 9 times and 3 times higher that of unactivated CoNi-LDH arrays and ECA-CoNi-LDH without hierarchical structure, respectively. Moreover, the ECA-CoFe-LDH also shows the possibility for practical applications in actual batteries. By coupling with a Fe2O3/C anode, the assembled aqueous battery delivered a large energy density of 184.4 Wh kg−1 at power density of 4 Wh kg−1 in high voltage range of 0–2 V. To our best knowledge, such high energy density and large working window of our assembled aqueous battery is exceeded other LDH-based aqueous battery or supercapacitor, and the energy density almost comparable than that of commercial Li-ion batteries. Moreover, almost no measurable capacitance losses can be detected even after 10000 cycles. In addition, this work also provides a strategy to develop a high energy density cathode for multiple metal-ion storage batteries.

Magnetic Resonance in metal-ion batteries: From NMR (Nuclear Magnetic Resonance) to EPR (Electron Paramagnetic Resonance)

Magnetic Resonance in metal-ion batteries: From NMR (Nuclear Magnetic Resonance) to EPR (Electron Paramagnetic Resonance)

New phases of MBenes M2B (M = Sc, Ti, and V) as high-capacity electrode materials for rechargeable magnesium ion batteries

Rechargeable magnesium ion batteries (MIBs) have attracted great interests as a prospective candidate for next generation large-scale energy storage systems owing to the low cost and high abundance of Mg resources. However, MIBs have been restricted by the lack of suitable electrode materials for a long term. Therefore, three new phases of two-dimensional transition metal borides (MBenes) including Sc2B, Ti2B and V2B are explored as electrode candidates for MIBs. All the three M2B (M = Sc, Ti, and V) with ground states of ferromagnetic configurations are proved dynamically and thermally stable by using phonon dispersions and molecular dynamics simulations. The results show that all M2B phases have ultra-high specific capacity of 3192.813 mA h/g, 3018.414 mA h/g and 2853.953 mA h/g for Mg on Sc2B, Ti2B and V2B, respectively. In addition, the M2B monolayer only undergoes a small change in lattice constant with adsorption of single layer or multilayer ions. This work not only reports three new phases of M2B with layered structure but also further provides useful information of MBenes as promising electrode candidates for high-performance metal ion batteries.

3D Ordered Porous Hybrid of ZnSe/N‐doped Carbon with Anomalously High Na+ Mobility and Ultrathin Solid Electrolyte Interphase for Sodium‐Ion Batteries

AbstractTransition metal selenides have been widely used in alkali metal ion batteries owing to their high specific capacities and low cost. However, their reaction kinetics and structural stability are usually poor during cycling, along with ambiguous differences in Li/Na/K‐storage behaviors. Herein, it is revealed that ZnSe possesses better Na+‐diffusion kinetics (including lower diffusion barrier, smaller activation energy, and higher diffusion coefficients) in comparison with Li+ and K+, as evidenced by theoretical calculations and electrochemical studies. The architectural designs of ZnSe‐based anode, including nitrogen‐doped carbon (N,C) and 3D ordered hierarchical pores (3DOHP) to form a 3DOHP ZnSe@N,C hybrid combined with regulating solid electrolyte interphase (SEI), significantly enhance Na+ reaction kinetics and accommodate volume changes. The resulting 3DOHP ZnSe@N,C electrodes exhibit outstanding rate capability and good cycling stability (241.6 mAh g−1 in sodium‐ion batteries (SIBs) at 10 A g−1 after 800 cycles), originating from improved electrical conductivity and shortened ion diffusion paths, accompanied by ultrathin and stable SEI with less Na2CO3/NaF in organic components and boosted Na2Se adsorption as sodiation. Moreover, the Na‐storage mechanism in 3DOHP ZnSe@N,C hybrid is further revealed by in situ studies. Accordingly, this study provides a new perspective for designing high‐performance electrode materials for SIBs.

Density-Based Descriptors of Redox Reactions Involving Transition Metal Compounds as a Reality-Anchored Framework: A Perspective

Description of redox reactions is critically important for understanding and rational design of materials for electrochemical technologies, including metal-ion batteries, catalytic surfaces, or redox-flow cells. Most of these technologies utilize redox-active transition metal compounds due to their rich chemistry and their beneficial physical and chemical properties for these types of applications. A century since its introduction, the concept of formal oxidation states (FOS) is still widely used for rationalization of the mechanisms of redox reactions, but there exists a well-documented discrepancy between FOS and the electron density-derived charge states of transition metal ions in their bulk and molecular compounds. We summarize our findings and those of others which suggest that density-driven descriptors are, in certain cases, better suited to characterize the mechanism of redox reactions, especially when anion redox is involved, which is the blind spot of the FOS ansatz.

Interfacial Model Deciphering High-Voltage Electrolytes for High Energy Density, High Safety, and Fast-Charging Lithium-Ion Batteries.

High-voltage lithium-ion batteries (LIBs) enabled by high-voltage electrolytes can effectively boost energy density and power density, which are critical requirements to achieve long travel distances, fast-charging, and reliable safety performance for electric vehicles. However, operating these batteries beyond the typical conditions of LIBs (4.3Vvs Li/Li+ ) leads to severe electrolyte decomposition, while interfacial side reactions remain elusive. These critical issues have become a bottleneck for developing electrolytes for applications in extreme conditions. Herein, an additive-free electrolyte is presented that affords high stability at high voltage (4.5VvsLi/Li+ ), lithium-dendrite-free features upon fast-charging operations (e.g., 162mAhg-1 at 3C), and superior long-term battery performance at low temperature. More importantly, a new solvation structure-related interfacial model is presented, incorporating molecular-scale interactions between the lithium-ion, anion, and solvents at the electrolyte-electrode interfaces to help interpret battery performance. This report is a pioneering study that explores the dynamic mutual-interaction interfacial behaviors on the lithium layered oxide cathode and graphite anode simultaneously in the battery. This interfacial model enables new insights into electrode performances that differ from the known solid electrolyte interphase approach to be revealed, and sets new guidelines for the design of versatile electrolytes for metal-ion batteries.

First-row transition metal compounds for aqueous metal ion batteries

In recent years, a series of aqueous metal ion batteries (AMIBs) has been developed to improve the safety and cost-efficiency of portable electronics and electric vehicles. However, the significant gaps in energy density, power density, and cycle stability of AMIBs directly hinder them from replacing the currently widely used non-aqueous metal ion batteries, which stems from the lack of reasonable configuration and performance optimization of electrode materials. First-row transition metal compounds (FRTMCs), with the advantages of optional voltage ranges (from low to high), adjustable crystal structures (layered and tunnel types with large spacing), and designable morphology (multi-dimensional nanostructures), are widely used to construct high-performance AMIBs. However, no comprehensive review papers were generated to highlight their specific and significant roles in AMIBs. In this review, we first summarize the superiority and characteristics of FRTMCs in AMIBs. Then, we put forward control strategies of FRTMCs from subsurface engineering to inner construction to promote capacitance control and diffusion control energy storage. After that, the electrochemical performance of the FRTMCs regulation strategies in AMIBs is reviewed. Finally, we present potential directions and challenges for further enhancements of FRTMCs in AMIBs. The review aims to provide an in-depth understanding of regulation strategies for enhancing energy storage to build high-performance AMIBs that meet practical applications.

Metal-Organic Frameworks for Metal-Ion Batteries: Towards Scalability

Metal-organic frameworks (MOFs), being a family of highly crystalline and porous materials, have attracted particular attention in material science due to their unprecedented chemical and structural tunability. Next to their application in gas adsorption, separation, and storage, MOFs also can be utilized for energy transfer and storage in batteries and supercapacitors. Based on recent studies, this review describes the latest developments about MOFs as structural elements of metal-ion battery with a focus on their industry-oriented and large-scale production.

Size-refinement enhanced flexibility and electrochemical performance of MXene electrodes for flexible waterproof supercapacitors

Increasing mechanical flexibility without sacrificing electrochemical performance of the electrode material is highly desired in the design of flexible electrochemical energy storage devices. In metal-related materials science, decreasing the grain size introduces more grain boundaries; this stops dislocations and crack propagation under deformation, and results in increased strength and toughness. However, such a size refinement effect has not been considered in the mechanical properties, particle stacking, wetting, and electrochemical performances of flexible supercapacitor electrodes. In this paper, MXene was used as an electrode material to study the size refinement effect of flexible supercapacitors. Size refinement improved the strength and toughness of the MXene electrodes, and this resulted in increased flexibility. Finite elemental analysis provided a theoretical understanding of size refinement-increased flexibility. Moreover, the size refinement also improved the specific surface area, electric conductance, ion transportation, and water wetting properties of the electrode, and the size refinement provided highly increased energy density and power density of the MXene supercapacitors. A highly flexible, water-proof supercapacitor was fabricated using size-refined MXene. The current study provides a new viewpoint for designing tough and flexible energy storage electrodes. The size refinement effect may also be applicable for metal ion batteries and electronic and photo devices composed of MXene and other nanoparticles.

Nitrogen-doped chain-like carbon nanospheres with tunable interlayer distance for superior pseudocapacitance-dominated zinc- and potassium-ion storage

Carbon-based materials have attracted extensive interest in metal-ion batteries owing to their low cost, good conductivity, and environmental friendliness. The practical application of graphite materials is associated with trade-offs in cyclability and energy density due to the sluggish kinetics. Herein, nitrogen-doped chain-like carbon nanospheres (NCN) with expanded interlayer distance are effectively fabricated by annealing carbon derived from aniline combustion. More impressively, the resulting NCN exhibits a chain-like structure and pyrrolic-N-dominated nitrogen doping, which not only facilitates charge transport but also provides chemically active sites for Zn- and K-ion storage. The above features lead to ultrafast ion storage in the NCN electrode via redox pseudocapacitive reactions, which endows NCN with enhanced kinetics and dramatic electrochemical performance: a remarkable energy density of 124.1 W h kg−1 for zinc-ion storage; superior reversible capacity (363.4 mA h g−1 at 0.1 A g−1), robust rate capability (120.3 mA h g−1 at 10 A g−1) and excellent cycling performance (193.8 mA h g−1 after 1000 cycles at 1 A g−1) for potassium-ion storage.

Bio-enzymatic synthesis of nitrogen-doped porous carbon/SnO2/carbon microspheres as high-performance composite materials for lithium-ion and sodium-ion batteries

In this study, a nitrogen-doped 3D porous starch-derived carbon/SnO2/carbon (PSC/SnO2/C) composite is synthesized with porous starch as a carbon source by biological enzymatic hydrolysis. Compared with the traditional complex acid-base reagent method, the biological enzymatic method is more environmentally friendly and economical, and it can also naturally introduce nitrogen sources and dope the carbon layer. Many mesoporous nanostructures provide enough buffer space and promote the ions' and electrons’ transmission rate. The formation of the Sn–O–C bond between SnO2 and carbon ensures the stability of the structure. As a result, the PSC/SnO2/C composite exhibits a high initial discharge capacity (1802 mAhg−1 at 0.2 A g−1 for LIBs and 549 mAh g−1 at 0.1 A g−1 for SIBs) and good cycle stability (701 mAh g−1 at 0.2 A g−1 after 100 cycles for LIBs and 271 mAh g−1 at 0.1 A g−1 after 100 cycles for SIBs). This synthesis method can prepare other energy storage systems such as fuel cells, supercapacitors, and metal ion batteries.