Calcium-ion Batteries Research Articles

A first-principles study of B3O3 monolayer as potential anode materials for calcium-ion batteries

A first-principles study of B3O3 monolayer as potential anode materials for calcium-ion batteries

Weak Solvation Effect Enhancing Capacity and Rate Performance of Vanadium‐Based Calcium Ion Batteries: A Strategy Guided by Donor Number

AbstractCalcium ion batteries (CIBs) are considered as an important candidate for post‐lithium energy storage devices due to their abundance of resources and low cost. However, CIBs still suffer from slow kinetics due to the large solvation structure and high desolvation energy of Ca2+ ions. Here, a solvation regulation strategy based on donor number (DN) is reported to achieve easy‐desolvation and rapid storage of Ca2+ in sodium vanadate (Na2V6O16·2H2O, NVO). Specially, the solvent with a low DN, represented by propylene carbonate (PC), forms the first solvation shell of calcium ions with weak binding energy and small shell structure, which facilitates the migration of Ca2+ in the electrolyte. More importantly, the low DN solvent is preferentially desolvated at the cathode/electrolyte interface, promoting the insertion of Ca2+ into the NVO electrode. Mechanism studies further confirm the highly reversible uptake/release of Ca2+ in the NVO cathode, along with the VO distance change in the coordination structure. Therefore, the NVO cathode achieves high capacity (376 mAh g−1 at 0.3 A g−1) and high‐rate performance (151 mAh g−1 at 5 A g−1). The weak solvation effect strategy further improves the electrochemical performance and provides great importance for the design of the long‐term development of CIBs.

Doping FePSe3 with Mg and Ca ions: A Density Functional Theory Study

The electronic and structural characteristics of FePSe3 doped with Mg and Ca were investigated using density functional theory (DFT) computations as implemented in the Quantum Espresso simulation package. The electronic conductivities of several Mg doped FePSe3 and Ca doped FePSe3 alloys were assessed in terms of density of states (DOS) and band structure. At the Fermi level, the electronic states of alloys such as, Fe1Mg1P2Se6, Fe2P2Se5Mg1, Fe1Ca1P2Se6 and Fe2P2Se5Ca1 suggest that they are non-metallic. While the electronic states of Fe2P1Mg1Se6 and Fe2P1Ca1Se6 are metallic. The alloys Fe1Mg1P2Se6 and Fe1Ca1P2Se6 have robust diffusion, according to structural analysis. Because of its shorter bond length of 2.67 Å, the Fe1Mg1P2Se6 alloy has the strongest ion diffusion into FePSe3. It also has the highest band gap of 1.62 eV, followed by Fe1Ca1P2Se6 at 1.50 eV. As seen in the alloys Fe1Mg1P2Se6 and Fe1Ca1P2Se6, the divalent ions Mg2+/Ca2+ prefer insertion into the Fe site of FePSe3. These alloys are potential materials for Magnesium ion batteries (MIB) and Calcium ion batteries (CIB) due to their stability and electronic conductivity.

Ultra‐High Capacity and Cyclability of β‐phase Ca0.14V2O5as a Promising Cathode in Calcium‐Ion Batteries

AbstractCrystalline water‐free β‐phase Ca0.14V2O5is reported for the first time as a viable cathode material for calcium‐ion batteries (CIBs). In contrast to layered α‐V2O5and δ‐CaxV2O5·nH2O, which have limited capacity, the β‐phase delivers a reversible capacity of ≈247 mAh g−1, which corresponds to the insertion/extraction of Ca2+between Ca0.14V2O5and Ca1.0V2O5. The process of Ca2+insertion process and the accompanying structural relaxation are theoretically and experimentally verified. The initial insertion of Ca2+into Ca0.14V2O5causes a slight shift of oxygen atoms surrounding hepta‐coordination sites, creating penta‐coordinated sites that are then partially filled up to Ca0.33V2O5. Further insertion occurs through the stepwise occupation of up to 50% of neighboring hexa‐ and tetra‐coordination sites to form Ca0.67V2O5and Ca1.0V2O5, respectively. The rearrangement of oxygen atoms in Ca0.14V2O5also minimizes dimensional changes, leading to high cyclic stability during repeated charge/discharge cycles. The remarkable electrochemical performance of full cells containing a Ca0.14V2O5cathode and a K metal anode in Ca2+/K+hybrid electrolytes, is also demonstrated, thanks to the inertness of K+insertion into Ca0.14V2O5and the absence of calcium plating/stripping. The cyclic stability and high capacity of Ca0.14V2O5is not compromised in hybrid electrolytes, making it a viable CIB cathode.

Calcium-ion thermal charging cell for advanced energy conversion and storage

Converting low-grade heat into electricity improves energy efficiency, reduces thermal pollution, and contributes to sustainability. However, the low thermal voltage, thermopower, or conversion efficiency of current monovalent-ion-based thermocells severely impede their application. Herein, we propose a new multivalent-ion-based calcium-ion thermal charging cell (CTCC) by introducing the concept of calcium-ion batteries into a thermoelectric system which demonstrates an ultrahigh thermopower of 25.2 mV K−1 through the synchronous thermo-extraction effect of oleic acid-treated Ca0.24V2O5·H2O electrode and thermodiffusion effect of electrolyte. The appealing calcium-ion energy carrier, favorable aqueous Ca(CF3SO3)2 electrolyte, and facile oleic acid modification strategy can ensure potentially higher voltage, enable fast diffusion kinetics, and prevent vanadium species from dissolution. As a result, the CTCC achieves ultrahigh thermal voltage of 1.149 V and Carnot-relative efficiency of 24.42% (± 0.22%) at a temperature difference of 45 K. This work enriches the multivalent-ion-based thermocell classes for efficient heat-to-electricity conversion in sustainable energy utilization.

Investigation of the electrochemical intercalation of Ca2+ into graphite layer carbon nano filaments as a novel electrode material for calcium-ion batteries

We investigated the electrochemical intercalation of Ca2+ or solvated Ca2+ into Marimo nano carbon (MNC) as an anode material for calcium-ion batteries. When Ca (ClO4)2 and Ca (TFSI)2 were used as electrolyte salts, the solution structure changed in the γ-butyrolactone solvent. Additionally, higher charge capacitance was obtained at the MNC electrode than at the graphite electrode. When heat-treated MNCs were used with each electrolyte (ClO4)2 intercalated better than Ca (TFSI)2.

Cu3(OH)2V2O7·2H2O@rGO with bimetallic redox activity as a novel cathode material for calcium–ion batteries

Owing to the abundance of calcium and low redox potential and high safety, calcium-ion batteries (CIBs) are considered a promising candidate for post lithium-ion batteries. Cu3(OH)2V2O7·2H2O@rGO with bimetallic redox activity is proposed as a novel cathode material for CIBs.

Exploring anodes for calcium-ion batteries

Calcium ion batteries have been increasingly explored as an alternative energy storage system as industry begins to manoeuvre towards an age of ‘Beyond lithium’ research and development.

B5N3 as a potential high-capacity electrode material for calcium ion batteries.

Calcium ion batteries (CIBs) are considered as promising candidates for the next-generation large-scale energy storage technologies, due to the abundant resources and bivalent properties of calcium. Herein, based on first principles calculations, we systematically explore the performance of B5N3 as an electrode material for chargeable CIBs. Specifically, the adsorption of the Ca atom effectively reduces the band gap of B5N3, leading to good electrical conductivity. Additionally, the B5N3 monolayer can achieve an effective double-layered adsorption of Ca atoms on both sides of the monolayer surface, thus exhibiting an ultra-high theoretical capacity of 4463 mA h g-1 (Ca) compared with the capacities of Na (2231 mA h g-1), Li (1116 mA h g-1) and K (558 mA h g-1). The high capacity is attributed to the multiple empty electron orbitals of the constituent elements of B5N3 and low distance mismatch which can exhibit excellent adsorption properties for multivalent atoms. Furthermore, the low diffusion energy barriers and satisfactory thermal stability ensure the reliability of B5N3 as a CIB electrode material. Our work not only develops an excellent candidate for the electrode materials of CIBs, but may also inspire the rational design and synthesis of electrode materials towards high-performance CIBs.

Anode chemistry in calcium ion batteries: A review

Large-scale energy storage and scientific research rapidly promote the research and exploration of calcium ion batteries (CIBs) due to the abundant reservation of calcium and the competitive redox potential of Ca/Ca 2+ . However, several critical issues hindered its development, especially the unsatisfactory performance of anode materials due to the poor plating/stripping reversibility Ca metal and sluggish de-solvation kinetics of Ca 2+ ion in the electrolyte. This review aims to provide a timely access to the state-of-art advance in anode chemistry of CIBs. Firstly, an overview on the development history of CIBs is presented. Then, a comprehensive understanding on the challenges facing CIBs is elaborated. The advancements on the development of appropriate salts and electrolytes to achieve highly reversible plating/stripping of calcium metal anode are systematically discussed. As alternative to metallic calcium anode, suitable anode candidates for hosting calcium ions are summarized, including alloying, intercalation, and organic electrodes systems. Finally, critical challenges for metallic calcium and alternative anode materials are envisioned, followed by their important future directions for the development and application in CIBs.

Evaluation of the role perfect and defect boron nitride monolayer in calcium ion batteries as a anode

In present work, anode materials of pristine boron nitride (BN) and its Stone-Wales defect (SW-BN) nanosheets have been studied for calcium ion batteries (CIBs), which include related cell voltage and theoretical capacity attributes, structural geometry variations, and Ca diffusion. Compared with the BN monolayer, Stone-Wales BN has superior conductivity as well as Ca adsorption properties. The more rapid mobility of Ca ion in SW-BN two-dimensional nanosheet is proved by lower diffusion barriers values (0.11 eV). Moreover, SW-BN has a proper open-circuit voltage (OCV) range to be employed as anode materials. The Highest theoretical capacity value of SW-BN could attain to 1162.66 mAh/g, which is about triple more than pristine BN (345 mAh/g). Therefore, anodes constructed by SW-BN nanosheets can be an appropriate option for CIBs.

Exploration of NaSICON Frameworks as Calcium-Ion Battery Electrodes

The development of energy storage technologies that are alternative to state-of-the-art lithium-ion batteries but exhibit similar energy densities, lower cost, and better safety is an important step in ensuring a sustainable energy future. Electrochemical systems based on calcium (Ca)-intercalation or deintercalation form such an alternative energy storage technology but require the development of intercalation electrode materials that exhibit reversible Ca-exchange with reasonable energy density and power density performance. To address this issue, we use first-principles calculations to screen over the wide chemical space of sodium superionic conductor (NaSICON) frameworks, with a chemical formula of CaxM2(ZO4)3 (where M = Ti, V, Cr, Mn, Fe, Co, or Ni and Z = Si, P, or S) for Ca electrode materials. We calculate the average Ca2+ intercalation voltage, the thermodynamic stability (at 0 K) of charged and discharged Ca-NaSICON, and the migration barriers of (meta)stable Ca-NaSICON compositions. Importantly, our calculations indicate CaxV2(PO4)3, CaxMn2(SO4)3, and CaxFe2(SO4)3 Ca-NaSICONs to be promising as Ca-cathodes. We find all silicate Ca-NaSICONs to be thermodynamically unstable and hence unsuitable as Ca-cathodes. We report the overall trends in the ground state Ca-vacancy configurations, besides voltages, stabilities, and migration barriers. Our work contributes to unearthing strategies for developing practical calcium-ion batteries, involving polyanionic intercalation frameworks.

BC2N nanotube as a promising anode for rechargeable calcium ion batteries

Because of cost-effective production and abundant resources of calcium, Ca-ion batteries (CIBs) are an appropriate option to alternate Li-ion batteries (LIBs). A new category of anode materials for CIBs has emerged since the successful synthesis of carbon nanotubes, which are B and N doped derivatives of it. For high-performance CIBs, BC2N nanotube (BC2NNT) has been studied as promising anode materials. In order to comprehend electrochemical attributes, cycling stability, and adsorption behavior of BC2NNT, first-principles computations have been executed. Based on nuclear magnetic resonance computations, two types of hexagonal rings (B2C2N2 (I) and BC4N (II)) were specified that are non-aromatic. Ca has adsorption on B2C2N2 and BC4N with adsorption energy (Ead) values of −47.44 and −28.50 kcal/mol, respectively. Specific capacity value has been determined to be as high as 840 mAh/g. The predicted average open-circuit voltage (OCV) for BC2NNT is 1.56 V, which has a larger value than that of other 2D materials. All mentioned reasons provide BC2NNT as an acceptable anode material for use in CIBs. In present research, results may create new ways of designing favorable boron-carbon-nitrogen based anode materials for CIBs.

Alloy Anodes for Nonaqueous Calcium-Ion Batteries

In the search to find new battery technologies that will extend current Li-ion technology towards the high-energy density and stability required for extended-range electric vehicles and efficient grid energy storage, earth-abundant working metal ions are increasingly being investigated. Calcium ion batteries are of interest due to calcium’s wide accessibility and abundance in the earth’s crust, but present novel challenges, such as sluggish diffusion kinetics and lack of known suitable intercalation hosts. The replacing of Ca metal anodes with new alloy materials that can work reversibly in current electrolyte systems is one practical route towards realizing the high voltage and capacity of a calcium battery. This complements current research in conventional Li-ion batteries to replace the conventional graphite anode by Group IIIA and IV elements. In this work, research into new alloy designs in novel electrochemical systems for Ca batteries will be explored and evaluated alongside key issues and challenges towards commercial applications.

Investigation of Transition Metal Oxide Post-Spinels for Calcium-Ion Batteries

The dependence on lithium for rising global energy demand coupled with the scarcity of lithium necessitates the exploration of post-lithium strategies. Calcium-ion batteries are one such post-lithium strategy that can mitigate rising costs owing to calcium’s natural abundancy. A critical gap in this field is the lack of cathodes capable of intercalating calcium at high voltages and capacities while also retaining structural stability. The handful of candidates evaluated thus far have been plagued by low capacities and poor cycling performance due to intercalation–induced phase changes and instability. Transition metal oxide post–spinel–type materials have been identified as potential candidates for reversible Ca–ion storage owing to their crystal structures and high theoretical energy densities. However, experimental validation of these theoretical predictions remains largely unaddressed. In this work, post-spinel Calcium Iron Oxide (CaFe2O4) and Calcium Manganese Oxide (CaMn2O4) are explored as cathodes for calcium-ion batteries. The redox activity of each cathode is investigated using galvanostatic (GS) cycling while their structural stabilities are evaluated with X-ray diffraction (XRD) and scanning electron microscopy (SEM). The use of GS in tandem with XRD and SEM provides insights into the evolution of crystal structure with Ca–ion–transport within each cathode. Our results reveal that these post–spinel systems can cycle with a reversible capacity of 56 mAh/g, making them promising cathode candidates for Ca–ion batteries and warrant further investigation.

(Digital Presentation) Advanced Intercalation Electrode Materials for Calcium Rechargeable Batteries

The growing demand for electric vehicles and stationary energy storage systems calls for developing next-generation batteries that combine high energy, high power and low cost. Among many post lithium-ion batteries, calcium rechargeable batteries utilizing divalent Ca2+ ion charge carriers are expected to offer clear benefits in affordability of batteries along with the potentially high energy density, due to the abundance of calcium in earth crust (46600 ppm versus 20 ppm for lithium) and the low redox potential of Ca/Ca2+ (-2.9 V vs. standard hydrogen electrode). Recent efforts on the development of negative electrodes, such as elemental calcium metal and natural graphite, has brought the rechargeable calcium chemistries a step closer to a practically feasible battery system. However, the lack of suitable cathode is the Achille’s heal of the calcium rechargeable battery technology.[1] The relatively large ionic radius and divalent nature of Ca ions make the intercalation kinetics generally sluggish in intercalation hosts. Moreover, a large Ca2+ intercalation is supposed to cause extended volume changes of the host, triggering a premature degradation of the electrode structure. In this talk, I would like to present our recent findings in graphite anode and polyanionic cathode materials as intercalation electrodes in high performance non-aqueous calcium rechargeable batteries. We demonstrated that a large amount of Ca ions can be reversibly (de)intercalation in graphite for Ca ion batteries by identifying a proper electrolyte to promote the solvated-ion co-intercalation reactions.[2] The solvated-Ca-ion co-intercalation chemistry is comprehensively investigated by combining first principle calculations and synchrotron in-situ X-ray diffraction. For cathodes, we find that the open-framework sodium vanadium fluorophosphate can function as a stable and fast-kinetic Ca2+ intercalation host with an extremely low capacity degradation rate of 0.02% per cycle over 500 cycles.[3] This value records the best stability reported for Ca ion battery cathodes so far. Through this talk, it is believed that the new findings in discovering novel materials or intercalation chemistries will be of great interest of the community working on multivalent ion batteries and other energy storage technologies.Reference:[1] C Chen, F Shi, ZL Xu, Advanced electrode materials for nonaqueous calcium rechargeable batteries, J. Mater. Chem. A, 2021, 9, 11908-11930[2] Z.L. Xu, J. Park, J. Wang, H. Moon, G. Yoon, J. Lim, Y.J. Ko, S.P. Cho, S.Y. Lee and K. Kang, A new high-voltage calcium intercalation host for ultra-stable and high-power calcium rechargeable batteries, Nat. Commun. 2021, doi:10.1038/s41467-021-23703-x.[3] J. Park,† Z.L. Xu,† G. Yoon,† S.K. Park, J. Wang, H. Hyun, H. Park, J. Lim, Y.J. Ko and K. Kang, Stable and High power calcium ion batteries enabled by calcium intercalation in graphite, Adv. Mater. 2020, 32.4: 1904411.

Adsorption and diffusion properties of calcium ions at the van der Waals interface of NbSe2-graphene 2D heterostructure for multivalent battery applications: density functional theory calculations

Multivalent-ion batteries such as calcium-ion batteries show promise as a high-density alternative to lithium-ion batteries which currently dominate the portable electronics market. In this work, the adsorption and diffusion properties of calcium ion at the van der Waals (vdW) interface of the 2D heterostructure formed by vertically stacking NbSe2 monolayer and graphene were investigated via density functional theory (DFT) calculations. Results showed that calcium can be effectively adsorbed on the vdW interface of the 2D heterostructure, with the binding energy of most stable site at −2.77 eV, much higher than most metal ions’ binding on pristine graphene. Thus, the NbSe2-graphene 2D heterostructure reinforced the binding of calcium ions at the interface. It is revealed that due to the random stacking nature of NbSe2 and graphene, a multi-path minimum energy pathways were identified at the van de Waals region, with relatively low diffusion barriers of around 0.20–0.50 eV. These indicate the capabilities of the 2D vdW heterostructure for fast multivalent ionic mobility and charge-discharge rate, while maintaining strong binding at the vdW interface. The results reveal NbSe2-graphene 2D vdW heterostructure’s potential as a promising anode material for multivalent battery applications.

Enhancing structural and cycle stability of Prussian blue cathode materials for calcium-ion batteries by introducing divalent Fe

Calcium-ion batteries (CIBs) have been of interest for rechargeable batteries due to their high energy density and fast ion diffusion in liquid electrolyte originated from the divalence and low charge/radius ratio of Ca ion. However, exploring high performance cathode materials for CIBs is very challenging. In this work, divalent Fe ions are introduced into copper hexacyanoferrate (CuHCF) to construct a new Prussian blue cathode material rich of Fe2+ by using K4Fe(CN)6 as the precursor instead of K3Fe(CN)6. The Fe2+ ions at low-spin state can improve the structural stability of CuHCF during Ca ions extraction and insertion processes effectively. It is found that the lattice parameter change of CuHCF is only 0.13 % during charge and discharge, much less than the CuHCF with Fe3+. X-ray absorption spectroscopy indicates that the charge compensation of CuHCF(Fe2+) is mainly contributed by Fe2+/Fe3+ redox couple. The octahedral distortion in CuHCF is also suppressed effectively. As a result, the CuHCF(Fe2+) cathode can deliver a reversible capacity of 54.5 mAh/g at 20 mA g−1 with a high capacity retention of 90.43 % after 1000 cycles.

Exploring the application of AlN graphyne in calcium ion batteries

Destiny functional theory (DFT) calculations are undertaken in order to scrutinize the electrochemical and calcium (Ca) storage characteristics of a graphyne-like aluminum nitride monolayer (G-AlNyen) as an electrode material for Ca-ion batteries (CIBs). The results show that the change in internal energy as well as the cell voltage values for the CIB with the G-AlNyen anode are comparable to others with two-dimensional 2D nano-materials. It is shown that Ca is adsorbed primarily onto the center of a hexagonal and triangular ring of G-AlNyen with absorption energies of −2.06 and −0.42 eV. After increasing the concentration of Ca atoms on G-AlNyen, the adsorption energy as well as the cell voltage decreases. Lower values of 0.15–0.32 eV related to the diffusion barrier confirm that the diffusion of Ca in the 2D nano-sheets is rapid. G-AlNyen shows a maximum theoretical capacity of approximately 869.23 mAh h g−1. The results are evaluated in terms of charge transfer, structure, energy as well as electronic characteristics and provide insight into the construction of better anode materials with higher capacity for the CIB.

Reversible and rapid calcium intercalation into molybdenum vanadium oxides

Looming concerns regarding scarcity, high prices, and safety threaten the long-term use of lithium in energy storage devices. Calcium has been explored in batteries because of its abundance and low cost, but the larger size and higher charge density of calcium ions relative to lithium impairs diffusion kinetics and cyclic stability. In this work, an aqueous calcium-ion battery is demonstrated using orthorhombic, trigonal, and tetragonal polymorphs of molybdenum vanadium oxide (MoVO) as a host for calcium ions. Orthorhombic and trigonal MoVOs outperform the tetragonal structure because large hexagonal and heptagonal tunnels are ubiquitous in such crystals, providing facile pathways for calcium-ion diffusion. For trigonal MoVO, a specific capacity of ∼203 mAh g-1 was obtained at 0.2C and at a 100 times faster rate of 20C, an ∼60 mAh g-1 capacity was achieved. The open-tunnel trigonal and orthorhombic polymorphs also promoted cyclic stability and reversibility. A review of the literature indicates that MoVO provides one of the best performances reported to date for the storage of calcium ions.