Aqueous rechargeable batteries are highly safe, low‐cost, and environmentally friendly, but restricted by low energy density. One of the most efficient solutions is to improve the concentration of the aqueous electrolytes. However, each salt is limited by its physical solubility, generally below 21–32 mol kg−1 (m). Here, a ZnCl2/ZnBr2/Zn(OAc)2 aqueous electrolyte with a record super‐solubility up to 75 m is reported, which breaks through the physical solubility limit. This is attributed to the formation of acetate‐capped water–salt oligomers bridged by Br−/Cl−‐H and Br−/Cl−/O‐Zn2+ interactions. Mass spectrometry indicates that acetate anions containing nonpolarized protons prohibit the overgrowth and precipitation of ionic oligomers. The polymer‐like glass transition temperature of such inorganic electrolytes is found at ≈−70 to −60 °C, without the observation of peaks for salt‐crystallization and water‐freezing from 40 to −80 °C. This supersoluble electrolyte enables high‐performance aqueous dual‐ion batteries that exhibit a reversible capacity of 605.7 mAh g−1, corresponding to an energy density of 908.5 Wh kg−1, with a coulombic efficiency of 98.07%. In situ X‐ray diffraction and Raman technologies reveal that such high ionic concentrations of the supersoluble electrolyte enable a stage‐1 intercalation of bromine into macroscopically assembled graphene cathode.
Feasible engineering of cathode electrolyte interphase enables the profoundly improved electrochemical properties in dual-ion battery
Aqueous electrolytes, which possess the advantages of nonflammability and high ionic conductivity for safe and sustainable energy storage systems, are restricted by their narrow potential windows due to water electrolysis. The recent study of high-voltage aqueous electrolytes has mainly focused on the molecular-level hydration structure of electrolyte salts, while the influence from subatomic-scale neutrons of the water solvent has never been considered. Here, for the first time, we report an electrochemical isotope effect in which the numerically increased neutrons in the water solvent extend the potential window of aqueous electrolytes. This effect is caused by the following factors: the lower zero-point energy of the deuterium compound, the smaller ion product, and the larger dehydration energy of heavy water. It is affected by ion species, electrolyte concentrations, and the ratio of deuterium to protium. Our finding provides the new insight into aqueous electrochemistry that the isotope in molecular water improves the performance of aqueous electrolytes.
10 W m −1 K −1 even at a high filler content (≈50 vol%). [3] Modulating vertical orientation of anisotropic nanofillers is a pronounced way for high throughplane thermal conductive composites. 2D nanosheets, such as graphene oxide and multilayer graphene, have been used as building blocks to form structurally anisotropic skeletons. [4] The highest throughplane thermal conductivity of such TIMs reaches 62.4 W m −1 K −1 with a graphene loading of 13.3 vol%. [5] However, achieving the higher through-plane thermal conductivity of TIMs under low filler contents remains challenging.Achieving high thermal conductivity of TIMs request high crystallite orientation, large crystallite size, and high density of skeleton. [6] Such perfect crystalline pathway of skeleton ensures high thermal conductivity of composites. [7] As a result, accurate control of vertical sheet alignment, high sheet content, and lower interface phonon scattering are three indispensable factors for producing advanced TIMs. 2D nanosheets typically have lateral dimensions less than 50 µm and a few atomic layer thicknesses. [8] The atom-thin and small-sized sheets render discontinuous crystalline domains and massive polymer/sheet interfaces when oriented vertically. In addition, the content of nanosheet liquid crystals is commonly below 30 mg g −1 because of strong steric and electrostatic repulsion. Low content of liquid crystals causes limited heat flux of skeleton, which rules out highly thermally conductive composites. Compared with colloidal nanosheets, giant sheets typically have much larger lateral dimensions of hundreds of microns and thicknesses of microns. [9] Selecting giant sheets as building blocks is promising, which provides a Excellent through-plane thermally conductive composites are highly demanded for efficient heat dissipation. Giant sheets have large crystalline domain and significantly reduce interface phonon scattering, making them promising to build highly thermally conductive composites. However, realizing vertical orientation of giant sheets remains challenging due to their enormous mass and huge hydrodynamic drag force. Here, we achieve highly vertically ordered liquid crystals of giant graphite oxide (more than 100 µm in lateral dimension) by microwire shearing, which endows the composite with a recorded through-plane thermal conductivity of 94 W m −1 K −1 . Microscale shearing fields induced by vertical motion of microwires conquer huge hydrodynamic energy barrier and vertically reorient giant sheets. The resulting liquid crystals exhibit extremely retarded relaxation and impart large-scale vertical array with bidirectional ordering degree as high as 0.82. The graphite array-based composites demonstrate an ultrahigh thermal enhancement efficiency of over 35 times per unit volume. Furthermore, the composites improve cooling efficiency by 93% for thermal management tests compared to commercial thermal interface materials. This work offers a novel methodology to precisely manipulate the orientation of giant particles and promo...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.