INHIBITION OF LITHIUM DENDRITE GROWTH USING ULTRA-THIN SUB-NANOMETER POROUS CARBON NANOMEMBRANE IN CONVENTIONAL AND SOLID-STATE LITHIUM-ION BATTERIES

An exemplary lithium-ion battery may include an anode, a cathode, and a separator between the anode and cathode. The separator may be at least partially coated with a sub-nanometer porous membrane. The battery may be a conventional battery in which the anode and cathode are at least partially submerged in an electrolytic solution. Alternatively, the battery may be a solid-state battery disposed between the anode and cathode and having a solid-state electrolyte, which may serve as the separator.

CROSS-REFERNCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Pat. Application No. 63/020,567 filed on May 6, 2020, the contents of which are hereby incorporated in its entirety.

TECHNICAL FIELD

This disclosure relates generally to a method of suppressing lithium dendrites for achieving high energy density batteries by the method of incorporating a nanomembrane in lithium-ion batteries, including conventional lithium-ion batteries using a separator and solid-state batteries those using a garnet-type solid-state electrolyte.

BACKGROUND

The present invention disclosed about the novel application of sub-nanometer porous carbon nanomembrane that enables the use of lithium metal as anodes in conventional and solid-state lithium-ion batteries. The existing Li-ion battery technology is insufficient to meet the future growing energy demands. Use of lithium metal anode is the best solution as it has the highest specific capacity (3861 mAh g-1) and paves a way to construct batteries with high energy density. However, use of lithium metal anode is hindered by the formation of lithium dendrites that reduces the coulombic efficiency. Further, the use of lithium metal anode in the existent technology is not possible due to safety issues arising from the chances of short-circuits during the propagation of lithium dendrites. As such, in the current technology, the use of lithium metal anode is not feasible. Instead, an anode material, graphite, ~10 orders lower capacity (372 mAh g-1) is used in the current technology.

Thus, there is a need to develop an improved lithium-ion battery that addresses the aforementioned challenges or shortcomings.

DETAILED DESCRIPTION

An exemplary lithium-ion battery may include an anode, a cathode, a separator between the anode and cathode, the separator being at least partially coated with a sub-nanometer porous membrane. Another exemplary lithium-ion battery may include an anode, a cathode, an electrolytic solution in which the anode and cathode are at least partially submerged, a separator between the anode and cathode, and a sub-nanometer porous membrane at least partially coating the separator. Yet another exemplary lithium-ion battery may include an anode, a cathode, a solid electrolyte disposed between the anode and cathode, and a sub-nanometer porous membrane at least partially coating the separator.

According to the present disclosure, the application of an ultrathin sub-nanometer porous carbon nanomembrane with lithium-ion batteries inhibits the mossy metal deposits (dendrite) propagation and its possibility to penetrate through the separator/solid electrolyte. The sub-nanometer porous carbon membrane may include one or more of the following properties to regulate the lithium-ion flux movement across the electrodes:

(i) Sub-nanometer porous with an average pore diameter of about 0.3 nm to about 0.9 nm, and with a pore density of about 1012pores per cm2to about 1014pores per cm2.

(ii) Ultra-thin membrane with a thickness of about 0.6 nm to 2.0 nm.

(iii) High mechanical strength with a Young’s modulus of about 5 GPA to about 500 GPa and high chemical stability with metallic lithium.

(iv) Electronically insulating with a relative dielectric constant of about 3-5.

The sub-nanometer porosity of the membrane may help in regulating the lithium-ion movement across the interface that ensures uniform lithium-ion flux, whereas the ultra-thin property offers negligible changes to the energy density of the battery. Further, the high mechanical strength of the membrane aids in suppressing the lithium dendrites, and the electronically insulating properties blocks any electron movement across the electrodes that is one of the critical issues in solid-state batteries. These multiple properties of the constructed membrane aid in the suppression of lithium dendrites growth across the electrodes.

Referring now to the figures,FIG.1illustrates a lithium-ion battery10according to one exemplary approach. The lithium-ion battery100may be a “conventional” battery having an anode102, a cathode104, and an electrolytic solution106in which the anode102and cathode104may be at least partially submerged. The anode102generally may be a lithium metal anode. The electrolytic solution106may include, but is not limited to, 1 M LiPF6in ethylene carbonate (EC) and dimethyl carbonate (DMC) in a 1:1 ratio. The lithium-ion battery100may also include a separator108between the anode102and the cathode104. The separator108may be, for example, a commercial Celgard separator.

The separator108may have a sub-nanometer porous membrane110coated on or around at least a portion of the separator108. The sub-nanometer porous membrane110generally may inhibit the mossy metal deposits (dendrite) propagation and its possibility to penetrate through the separator108and may regulate the lithium-ion flux movement across the electrodes. In embodiments, the sub-nanometer porous membrane110may have an average pore diameter ranging between about 0.3 nm and about 0.9 nm. The sub-nanometer porous membrane110may have a pore density ranging between about 1012pores per cm2and about 1014pores per cm2. The sub-nanometer porous membrane110may have a thickness ranging between about 0.6 nm and 2.0 nm. For example, the sub-nanometer porous membrane110may be and/or may incorporate a carbon nanomembrane (CNM). CNMs are two-dimensional layers or sheets with a nanometer thickness, such as described in an article titled “Carbon Nanomembranes” published inAdvanced Materialsin 2016, which is incorporated by reference herein.

With embodiments, the sub-nanometer porous membrane110may have a Young’s Modulus ranging between about 5 GPa and about 500 GPa, more particularly, between about 5 GPa and 50 GPa. The sub-nanometer porous membrane110may have high chemical stability with, lithium, including, but not limited to, lithium ions, metallic lithium, and the like. The sub-nanometer porous membrane110further may be electronically insulating, for example and without limitation, have a relative dielectric constant of about 3 to about 5.

The sub-nanometer porosity of the membrane110may help in regulating the lithium-ion movement across the interface that ensures uniform lithium-ion flux, whereas the ultra-thin property offers negligible changes to the energy density of the battery. Further, the high mechanical strength of the membrane110aids in suppressing the lithium dendrites, and the electronically insulating properties at least partially or at least substantially blocks any electron movement across the electrodes that is one of the critical issues in solid-state batteries. These multiple properties of the constructed membrane110aid in the suppression of lithium dendrites growth across the electrodes.

The sub-nanometer porous membrane110may be applied as a single layer or as a double layer.

Referring now toFIG.2AthroughFIG.4, the results of various dendrites testing on a symmetrical cell of a lithium-ion battery as described above are illustrated. As seen in the results, the lithium-ion battery with a single layer of the sub-nanometer porous membrane had very high performance compared to the lithium-ion battery without a sub-nanometer porous membrane and to the lithium-ion battery with double layers of the sub-nanometer porous membrane. As further seen in the results, the double layer coated separators had high polarization.

Referring now toFIG.5, a lithium-ion battery200according to another exemplary approach is illustrated. In particular, the lithium-ion battery200may be an all-solid-state battery in which a solid electrolyte206may be disposed between the anode202and the cathode204. As with the embodiment ofFIG.1, the anode generally may be a lithium metal anode. The solid electrolyte206may be a garnet-type electrolyte, for example and without limitation, Li6.5La3Zr1.5Ta6.5O12(LLZT).

The solid electrolyte206may have a sub-nanometer porous membrane210coated on or around at least a portion of the solid electrolyte206. As with the embodiment ofFIG.1, the sub-nanometer porous membrane210generally may inhibit the mossy metal deposits (dendrite) propagation and its possibility to penetrate through the solid electrolyte206and may regulate the lithium-ion flux movement across the electrodes. In embodiments, the sub-nanometer porous membrane210may have an average pore diameter ranging between about 0.3 nm and about 0.9 nm. The sub-nanometer porous membrane210may have a pore density ranging between about 1012pores per cm2and 1014pores per cm2. The sub-nanometer porous membrane210may have a thickness ranging between about 0.6 nm and 2.0 nm. For example, the sub-nanometer porous membrane210may be and/or may incorporate a carbon nanomembrane (CNM). With embodiments, the sub-nanometer porous membrane210may have a Young’s Modulus ranging between about 5 GPa to about 500 GPa, more particularly, between about 5 GPa and 50 GPa. The sub-nanometer porous membrane210may have high chemical stability with metallic lithium. The sub-nanometer porous membrane210further may be electronically insulating, for example and without limitation, have a relative dielectric constant of about 3 to about 5.

The sub-nanometer porous membrane210may be applied as a single layer or as a double layer.

Referring now toFIG.6throughFIG.7D, the results of various dendrites testing on a symmetrical cell200are illustrated. As seen in the results, the Li symmetrical cell with a single layer of the sub-nanometer porous membrane210also had very high performance.

As further seen in the Electrical Impedance Spectroscopy (EIS) measurements illustrated inFIG.8, there was very negligible increase in impedance before and after cycling. All solid-state studies were done at 60° C. The double layer coated nano-porous membrane was found to be highly stable even at a current density of 0.7 mA cm-2. This would be of great interest to industries as very high performance is achieved with stable polarization.

The use of the sub-nanometer porous membrane110,210for both the conventional lithium-ion battery100and the all-solid-state battery200removes the barrier of using lithium metal anodes, which has the highest theoretical capacity of 3861 mAh g-1. Further, the critical current density of garnet-type solid-state electrolyte was found to be very low, which has been improved by several times by incorporating the nano-porous membrane into the battery.

The lithium-ion battery incorporating the sub-nanometer porous membrane has the following advantages: high energy density, better safety, use of lithium metal anode, and high critical current density.

While the disclosed materials have been described in detail in connection with only a limited number of embodiments, it should be readily understood that the embodiments are not limited to such disclosed embodiments. Rather, that disclosed can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the disclosed materials. Additionally, while various embodiments have been described, it is to be understood that disclosed aspects may include only some of the described embodiments. Accordingly, that disclosed is not to be seen as limited by the foregoing description but is only limited by the scope of the appended claims.