Method of activating two-dimensional materials for multivalent/polyatomic-ion intercalation battery electrodes

Abstract

A method for activating two-dimensional host materials for a multivalent / polyatomic ion battery may include adding a pillaring salt in electrolyte. This process may be followed by in-situ electrochemically intercalating the pillaring ions, solvent molecules and multivalent ions into the van der Waals gap of host materials. After the activation process, the host material is transformed into an interlayer-expanded 2D material with significantly enhanced specific capacity and rate performance for multivalent ion intercalation.

Description

RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Patent Application No. 62 / 181,873 filed on Jun. 19, 2015, which is incorporated herein by reference.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH[0002]This invention was made with government support under Grant No. N00014-13-1-0543 awarded by the Office of Naval Research. The government has certain rights in the invention.FIELD OF THE INVENTION[0003]This invention relates to multivalent / polyatomic-ion batteries. More particularly, to a method for activating two-dimensional materials as high-capacity and high-rate intercalation electrodes in such batteries.BACKGROUND OF INVENTION[0004]The first rechargeable magnesium battery was proposed in as early as 2000, which delivered an energy density only comparable to Ni—Cd batteries. Surprisingly, this material still represents one of the most successful cathode materials for rechargeable magnesium batteries after more than ten years of R&D in this field. F...

AI Technical Summary

Benefits of technology

The patent describes a method for activating host materials for a new type of battery using two-dimensional materials. By adding a certain salt and then conducting electrochemistry, the host material is transformed into an expanded two-dimensional material with improved capacity and performance for a certain type of ion. This method also results in a larger space between the layers of the material, which allows for easier movement of the ions. The use of polyatomic ions, particularly magnesium, is also shown to improve the battery's performance.

Problems solved by technology

These results reflect the intrinsic difficulty of electrochemical storage of multivalent cations in insertion compounds.

These characteristics indicate the high polarization strength of multivalent cation, and result in strong electronic interaction between the cations and the negatively charged coordinating atoms in the insertion host, which in turn leads to unfavorable insertion and diffusion.

The insertion / diffusion of these cations are sluggish in common frameworks that work well for lithium.

For oxides, no practical cycling stability has been reported.

To date, there is no cathode material exhibiting practical energy density and cyclability suitable for electrochemical storage of multivalent metal ions.

In particular, there has been no demonstration of an Mg ion full cell with higher than 2V voltage, which includes an Mg insertion cathode, an Mg anode and a compatible electrolyte.

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