Solid electrolyte separator bonding agent

Abstract

Set forth herein are electrochemical cells which include a negative electrode current collector, a lithium metal negative electrode, an oxide electrolyte membrane, a bonding agent layer, a positive electrode, and a positive electrode current collector. The bonding agent layer advantageously lowers the interfacial impedance of the oxide electrolyte at least at the positive electrode interface and also optionally acts as an adhesive between the solid electrolyte separator and the positive electrode interface. Also set forth herein are methods of making these bonding agent layers including, but not limited to, methods of preparing and depositing precursor solutions which form these bonding agent layers. Set forth herein, additionally, are methods of using these electrochemical cells.

Description

BACKGROUND[0001]This application claims priority to, and the benefit of, US Provisional Patent Application No. 62 / 336,474, filed, May 13, 2016, entitled SOLID ELECTROLYTE SEPARATOR BONDING AGENT, and US Provisional Patent Application No. 62 / 448,294, filed Jan. 19, 2017, entitled SOLID ELECTROLYTE SEPARATOR BONDING AGENT, the entire contents of each of which are herein incorporated by reference in their entirety for all purposes.[0002]In a rechargeable Li+ ion battery, Li+ ions move from a negative electrode to a positive electrode during discharge and in the opposite direction during charge. This process produces electrical energy (Energy=Voltage×Current) in a circuit connecting the electrodes, which is electrically insulated from, but parallel to, the Li+ ion conduction path. The battery's voltage (V versus Li) is a function of the chemical potential difference for Li situated in the positive electrode as compared to the negative electrode and is maximized when Li metal is used as ...

AI Technical Summary

Benefits of technology

[0007]In one embodiment, the instant disclosure sets forth an electrochemical stack which includes a lithium metal (Li) negative electrode, a positive electrode, an electrolyte separator in direct contact with the Li metal negative electrode, and a bonding layer comprising a lithium salt, a polymer, and a solvent. In some examples, the bonding layer is a gel electrolyte. The bonding layer directly contacts, and is positioned between, the electrolyte separator and the positive electrode, and the electrolyte separator protects the Li metal negative electrode from exposure to the polymer or to the solvent, or both, in the bonding layer. As described herein, ...

Problems solved by technology

However, liquid electrolytes suffer from several problems including flammability during thermal runaway, outgassing at high voltages, and chemical incompatibility with lithium metal negative electrodes.

Despite these advantages, solid electrolytes are still insufficient in several regards for commercial applications.

Moreover, even in the absence of delamination, solid interfaces tend not to perfectly align with each other.

If a solid lithium metal negative electrode is laminated to a solid electrolyte, and the solid electrolyte (i.e., separator), on the opposing side, is laminated to a positive electrode, each solid interface (Li-separator & Separator-Cathode) may have insufficient electrical contact due to areas where one solid interface does not perfectly align and contact another solid interface.

Areas of non-contact between the solid electrolyte and the positive electrode result in impedance rises which reduce a battery's power and capacity.

To date and the best of Applicant's knowledge, there are no public disclosures of commercially viable solid electrolyte separators which interface with a solid positive electrode with a sufficient...

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