Most reported cathodes of nonaqueous dual‐ion batteries (DIBs) host anions via insertion reactions. It is necessary to explore new cathode chemistry to increase the battery energy density. To date, transition metals have yet to be investigated for nonaqueous DIBs, albeit they may offer high capacity in anodic conversion reactions. Here, we report that bulk copper powder exhibits a high reversible capacity of 762 mAh g−1at 3.2 V vs. Li+/Li and relatively stable cycling in common organic electrolytes. The operation of the copper electrode is coupled with the transfer of anion charge carriers. An anion exchange membrane separator is employed to prevent Cu2+from crossing from the catholyte to the anode side. We designed an unbalanced electrolyte with a more concentrated anolyte than a catholyte. This addresses the concentration overpotential ensued during charge and facilitates the high specific capacity and enhanced reversibility. This finding provides a promising direction for high‐energy DIBs.
Most reported cathodes of nonaqueous dual‐ion batteries (DIBs) host anions via insertion reactions. It is necessary to explore new cathode chemistry to increase the battery energy density. To date, transition metals have yet to be investigated for nonaqueous DIBs, albeit they may offer high capacity in anodic conversion reactions. Here, we report that bulk copper powder exhibits a high reversible capacity of 762 mAh g−1at 3.2 V vs. Li+/Li and relatively stable cycling in common organic electrolytes. The operation of the copper electrode is coupled with the transfer of anion charge carriers. An anion exchange membrane separator is employed to prevent Cu2+from crossing from the catholyte to the anode side. We designed an unbalanced electrolyte with a more concentrated anolyte than a catholyte. This addresses the concentration overpotential ensued during charge and facilitates the high specific capacity and enhanced reversibility. This finding provides a promising direction for high‐energy DIBs.
more » « less- Award ID(s):
- 2215645
- NSF-PAR ID:
- 10380262
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 61
- Issue:
- 47
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract -
more » « less
Abstract Nonaqueous metal–gas batteries based on halogenated reactants exhibit strong potential for future high‐energy electrochemical systems. The lithium–sulfur hexafluoride (Li–SF6) primary battery, which utilizes a safe, noncombustible, energy‐dense gas as cathode, demonstrates attractive eight‐electron transfer reduction during discharge and high attainable capacities (>3000 mAh g−1carbon) at voltages above 2.2 VLi. However, improved rate capability is needed for practical applications. Here, two viable strategies are reported to achieve this by targeting the solubility of the passivating discharge product, lithium fluoride (LiF). Operating at moderately elevated temperatures, e.g., 50 °C, in DMSO dramatically improves LiF solubility and promotes sparser and larger LiF nuclei on gas diffusion layer electrodes, leading to capacity improvements of ≈10× at 120 µA cm−2. More aggressive chemical modification of the electrolyte by including a tris(pentafluorophenyl)borane anion receptor further promotes LiF solubilization; capacity increases even at room temperature by a factor of 25 at 120 µA cm−2, with attainable capacities up to 3 mAh cm−2. This work shows that bulk fluoride‐forming conversion reactions can be strongly manipulated by tuning the electrolyte environment to be solvating toward F−, and that significantly improved rates can be achieved, leading a step closer to practical applications.
-
more » « less
Abstract New acceptor‐type graphite intercalation compounds (GICs) offer candidates of cathode materials for dual‐ion batteries (DIBs), where superhalides represent the emerging anion charge carriers for such batteries. Here, the reversible insertion of [LiCl2]−into graphite from an aqueous deep eutectic solvent electrolyte of 20
m LiCl+ 20m choline chloride is reported. [LiCl2]−is the primary anion species in this electrolyte as revealed by the femtosecond stimulated Raman spectroscopy results, particularly through the rarely observed H–O–H bending mode. The insertion of Li–Cl anionic species is suggested by7Li magic angle spinning nuclear magnetic resonance results that describe a unique chemical environment of Li+ions with electron donors around.2H nuclear magnetic resonance results suggest that water molecules are co‐inserted into graphite. Density functional theory calculations reveal that the anionic insertion of hydrated [LiCl2]−takes place at a lower potential, being more favorable. X‐ray diffraction and the Raman results show that the insertion of [LiCl2]−creates turbostratic structure in graphite instead of forming long‐range ordered GICs. The storage of [LiCl2]−in graphite as a cathode for DIBs offers a capacity of 114 mAh g−1that is stable over 440 cycles. -
more » « less
Abstract Dual‐ion batteries that use anions and cations as charge carriers represent a promising energy‐storage technology. However, an uncharted area is to explore transition metals as electrodes to host carbonate in conversion reactions. Here we report the reversible conversion reaction from copper to Cu2CO3(OH)2, where the copper electrode comprising K2CO3and KOH solid is self‐sufficient with anion‐charge carriers. This electrode dissociates and associates K+ions during battery charge and discharge. The copper active mass and the anion‐bearing cathode exhibit a reversible capacity of 664 mAh g−1and 299 mAh g−1, respectively, and relatively stable cycling in a saturated mixture electrolyte of K2CO3and KOH. The results open an avenue to use carbonate as a charge carrier for batteries to serve for the consumption and storage of CO2.
-
more » « less
Abstract Dual‐ion batteries that use anions and cations as charge carriers represent a promising energy‐storage technology. However, an uncharted area is to explore transition metals as electrodes to host carbonate in conversion reactions. Here we report the reversible conversion reaction from copper to Cu2CO3(OH)2, where the copper electrode comprising K2CO3and KOH solid is self‐sufficient with anion‐charge carriers. This electrode dissociates and associates K+ions during battery charge and discharge. The copper active mass and the anion‐bearing cathode exhibit a reversible capacity of 664 mAh g−1and 299 mAh g−1, respectively, and relatively stable cycling in a saturated mixture electrolyte of K2CO3and KOH. The results open an avenue to use carbonate as a charge carrier for batteries to serve for the consumption and storage of CO2.
