As new uses for larger scale energy storage systems are realized, new chemistries that are less expensive or have higher energy density are needed. While lithium-ion systems have been well studied, ...the availability of new energy storage chemistries opens up the possibilities for more diverse strategies and uses. One potential path to achieving this goal is to explore chemistries where a multivalent ion such as Ca2+ or Mg2+ is the active species. Herein, we demonstrate this concept for a Ca-ion system utilizing manganese hexacyanoferrate (MFCN) as the cathode to intercalate Ca reversibly in a dry nonaqueous electrolyte. Through characterization via X-ray absorption near-edge spectroscopy, it is determined that only the manganese changes oxidation state during cycling with Ca. X-ray diffraction indicates the MFCN maintains its crystallinity during cycling, with only minor structural changes associated with expansion and contraction. Furthermore, we have demonstrated the first rechargeable Ca-ion battery utilizing MFCN as the cathode and elemental tin as the anode.
Energy storage emerging Trahey, Lynn; Brushett, Fikile R.; Balsara, Nitash P. ...
Proceedings of the National Academy of Sciences - PNAS,
06/2020, Letnik:
117, Številka:
23
Journal Article
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Energy storage is an integral part of modern society. A contemporary example is the lithium (Li)-ion battery, which enabled the launch of the personal electronics revolution in 1991 and the first ...commercial electric vehicles in 2010. Most recently, Li-ion batteries have expanded into the electricity grid to firm variable renewable generation, increasing the efficiency and effectiveness of transmission and distribution. Important applications continue to emerge including decarbonization of heavy-duty vehicles, rail, maritime shipping, and aviation and the growth of renewable electricity and storage on the grid. This perspective compares energy storage needs and priorities in 2010 with those now and those emerging over the next few decades. The diversity of demands for energy storage requires a diversity of purpose-built batteries designed to meet disparate applications. Advances in the frontier of battery research to achieve transformative performance spanning energy and power density, capacity, charge/discharge times, cost, lifetime, and safety are highlighted, along with strategic research refinements made by the Joint Center for Energy Storage Research (JCESR) and the broader community to accommodate the changing storage needs and priorities. Innovative experimental tools with higher spatial and temporal resolution, in situ and operando characterization, first-principles simulation, high throughput computation, machine learning, and artificial intelligence work collectively to reveal the origins of the electrochemical phenomena that enable new means of energy storage. This knowledge allows a constructionist approach to materials, chemistries, and architectures, where each atom or molecule plays a prescribed role in realizing batteries with unique performance profiles suitable for emergent demands.
Future energy applications rely on our ability to tune liquid intermolecular interactions and achieve designer electrolytes with highly optimized properties. In this work, we demonstrate rational, ...combined experimental–computational design of a new carba-closo-dodecaborate-based salt with enhanced anodic stability for Mg energy storage applications. We first establish, through a careful examination using a range of solvents, the anodic oxidation of a parent anion, the carba-closo-dodecaborate anion at 4.6 V vs Mg0/2+ (2.0 vs Fc0/+), a value lower than that projected for this anion in organic solvent-based electrolytes and lower than weakly associating bis(trifluoromethylsulfonyl)imide and tetrafluoroborate anions. Solvents such as acetonitrile, 3-methylsulfolane, and 1,1,1,3,3,3-hexafluoroisopropanol are shown to enable the direct measurement of carba-closo-dodecaborate oxidation, where the resultant neutral radical drives passive film formation on the electrode. Second, we employ computational screening to evaluate the impact of functionalization of the parent anion on its stability and find that replacement of the carbon-vertex proton with a more electronegative fluorine or trifluoromethyl ligand increases the oxidative stability and decreases the contact-ion pair formation energy while maintaining reductive stability. This predicted expansion of the electrochemical window for fluorocarba-closo-dodecaborate is experimentally validated. Future work includes evaluation of the viability of these derivative anions as efficient and stable carriers for energy storage as a function of the ionic transport through the resulting surface films formed on candidate cathodes.
New energy storage chemistries based on Mg ions or Ca ions can theoretically improve both the energy density and reduce the costs of batteries. To date there has been limited progress in implementing ...these systems due to the challenge of finding a high voltage high capacity cathode that is compatible with an electrolyte that can plate and strip the elemental metal. In order to accelerate the discovery of such a system, model systems are needed that alleviate some of the issues of incompatibility. This report demonstrates the ability of nickel hexacyanoferrate to electrochemically intercalate Mg, Ca and Zn ions from a nonaqueous electrolyte. This material has a relatively high insertion potential and low overpotential in the electrolytes used in this study. Furthermore, since it is not an oxide based cathode it should be able to resist attack by corrosive electrolytes such as the chloride containing electrolytes that are often used to plate and strip magnesium. This makes it an excellent cathode for use in developing and understanding the complex electrochemistry of multivalent ion batteries.
•Nickel hexacyanoferrate is shown to electrochemically insert Mg, Ca and Zn ions.•Intercalation voltages are 2.9 V, 2.6 V, and 1.2 V for Mg, Ca and Zn, respectively.•Changes to composition, structure, and iron oxidation state are observed.•The electrochemistry is reversible.
The Ca2+ solvation structure at the electrolyte/electrode interface is of central importance to understand electroreduction stability and solid–electrolyte interphase (SEI) formation for the novel ...multivalent Ca battery systems. Using an exemplar electrolyte, the concentration-dependent solvation structure of Ca(BH4)2-tetrahydrofuran on a gold model electrode has been investigated with various electrolyte concentrations via electrochemical quartz crystal microbalance with dissipation (EQCM-D) and X-ray photoelectron spectroscopy (XPS). For the first time, in situ EQCM-D results prove that the prevalent species adsorbed at the interface is CaBH4 + across all concentrations. As the salt concentration increases, the number of BH4 – anions associated with Ca2+ increases, and much larger solvated complexes such as CaBH4 +·4THF or Ca(BH4)3 –·4THF form at the interface at high concentrations prior to Ca plating. Different interfacial chemistries lead to the formation of SEIs with different components demonstrated by XPS. High electrolyte concentrations reduce the solvent decomposition and promote the formation of thick, uniform, and inorganic-rich (i.e., CaO) SEI layers, which contribute to improved Ca plating efficiency and current density in electrochemical measurements.
The Mg battery is an energy storage technology which has garnered significant interest in recent years. Mg batteries incorporating a metal oxide cathode (MOC) are potential candidates to supersede ...the state-of-the-art Li-ion battery in energy density, cost, and sustainability. However, there are significant discrepancies in reported performances and reactivities of Mg battery MOCs, with detailed analyses revealing that parasitic electrolyte reactions can contribute almost entirely to the measured capacity. This Perspective describes a holistic approachencompassing elemental, redox, and structural probeswhich is vital to robustly confirm and quantify Mg intercalation in MOCs. It critically surveys recent literature for applications of this approach to reveal true state-of-the-art MOCs for Mg batteries. We also suggest testing and analysis protocols to ensure fair comparison of future reports with these state-of-the-art materials.
The energy density and cost of battery systems, relative to the current state-of-the art, can be improved by developing alternative chemistries utilizing multivalent working ions such as calcium. ...Many challenges must be overcome, such as the identification of cathode materials with high energy density and an electrolyte with a wide electrochemical stability window that can plate and strip calcium metal, before market implementation. Herein, the feasibility and cycling performance of Ca2+ intercalation into a desodiated layered Na2FePO4F host is described. This is the first demonstration of Ca2+ intercalation into a polyanionic framework, which implies that other polyanionic framework materials may be active for Ca2+ intercalation. Although substantial effort is expected in order to develop a high energy density cathode material, this study demonstrates the feasibility of Ca2+ intercalation into multiple host structures types, thereby extending opportunities for development of Ca insertion host structures, suggesting such a cathode material can be identified and developed.
•Reversible Ca2+ intercalation into a polyanionic framework host structure.•High energy density chemistry for next-generation energy storage systems.•Interface transport should be maximized by investigating complementary electrolytes.
The future of high-voltage rechargeable batteries is closely tied to the fundamental understanding of the processes that lead to the potential-dependent degradation of electrode materials and organic ...electrolytes. To date, however, there have been no methods able to provide quantitative, in situ and in real time information about the electrode dissolution kinetics and concomitant electrolyte decomposition during charge/discharge. We describe the development of such a method, which is of both fundamental and technological significance. Our novel approach enables simultaneous and independent measurements of transition-metal cation dissolution rates from different oxide hosts (Co3+/4+ or Cr3+/4+), deintercalation kinetics of working cations (Mg2+), and the relative rate of electrolyte decomposition.
High conductivity solid electrolytes are promising solutions for extremely high energy density battery systems including Li/air and Li/sulfur. Lithium aluminum titanium phosphate (LATP) ceramics have ...among the highest reported ionic conductivities and are promising candidates as solid electrolytes. Li1.3Al0.3Ti1.7(PO4)3 powders were synthesized for the first time via a solution-based method at synthesis temperatures as low as 650 °C. The ceramic powders are characterized using X-ray powder diffraction, solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The effect of Li and Al local structure and the presence of amorphous and crystalline impurities on electrolyte morphology and sinterability have been studied in detail.
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