Patent Publication Number: US-2021184247-A1

Title: 6Li BATTERY

Description:
FIELD 
     The present invention relates to advanced battery technology, and more particularly, to an advanced battery technology that uses isotopically pure  6 lithium ( 6 Li). 
     BACKGROUND 
     Lithium ion (Li-ion) batteries use lithium mined from the Earth. The lithium mined from the Earth has natural abundance lithium, which is only between 3-8%  6 Li. It should be noted that there are two stable isotopes of lithium— 6 Li and  7 Li—with  7 Li having an extra neutron compared to  6 Li. Conventional Li-ion batteries use the natural abundance lithium, which is a mixture of  6 Li and  7 Li, but whose properties are primarily that of  7 Li. These conventional Li-ion batteries are limited in discharge power and cycling life compared to  6 Li batteries. The less massive  6 Li ions enable faster charge transport (increased power), higher ionic diffusion (better low temperature performance) and less electrode stress (longer life) then compared to natural abundance lithium batteries. 
     Accordingly, an improved battery technology that uses isotopically pure or enriched  6 Li may be more beneficial. 
     SUMMARY 
     Certain embodiments of the present invention may provide solutions to the problems and needs in the art that have not yet been fully identified, appreciated, or solved by current advanced battery technologies. For example, some embodiments of the present invention pertain to advanced battery technology that uses isotopically pure  6 Li. For example, some embodiments increase the power of a Li-ion battery as well as increase the cycle life of the battery. 
     In an embodiment, a battery may include electrolyte salt and electrode material fabricated from isotopically pure or otherwise enriched in  6 Li to increase power and life of the battery. 
     In another embodiment, an isotopically pure battery or battery enriched in  6 Li is configured to increase round trip energy efficiency of storage, increase usable power of the  6 Li battery, and reduce wear and mechanical degradation on the  6 Li. 
     In yet another embodiment, a battery enriched in isotopically  6 Li is configured to increase round trip energy efficiency of storage, increase usable power of the  6 Li battery, and reduce wear and mechanical degradation on the  6 Li. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the advantages of certain embodiments of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. While it should be understood that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which: 
         FIG. 1  is block diagram illustrating a battery, according to an embodiment of the present invention. 
         FIG. 2A  is a diagram illustrating a battery having a plurality of layers diffused with  6 Li and  7 Li, according to an embodiment of the present invention. 
         FIG. 2B  is a diagram illustrating a battery having a plurality of layers diffused with  6 Li, according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Some embodiments generally pertain to an isotopically pure or isotopically enriched  6 Li-ion battery. Lithium has been shown to demonstrate the kinetic isotope effect in both diffusion transport in liquid electrolytes as well as in solid state electrolytes. This effect means that transport of the less massive  6 Li ion is faster than for the more massive  7 Li ion. 
     Additionally,  6 Li has been shown to be preferentially intercalated into battery materials as compared to  7 Li, causing less strain and fatigue on the battery material during cycling. The effect increases the round trip energy efficiency of storage, increases the usable power of a  6 Li battery, and reduces the wear or mechanical degradation on the battery and battery materials from operation. 
     In certain embodiments, the battery uses electrolyte salts and electrode materials fabricated using isotopically pure or isotopically enriched  6 Li precursors as opposed to natural abundance Li. In nature, the fraction of Li as  6 Li varies from 3-8%. These natural sources have varying isotopic abundances, specifically due to the kinetic isotope effect in nature enriching sources in  6 Li. 
     Li-ion batteries are the key driving technology for electric vehicles. They are also key components in the personal electronics industry. The use of  6 Li in battery technology will increase both the power and cycle life of any Li-ion batteries where it used. 
     Since  6 Li is less massive than  7 Li,  6 Li is transported more quickly through ion conducting materials in solid state batteries. The diffusion flux of lithium through a medium (electrolyte or solid electrode) is partially dependent on lithium&#39;s diffusivity, which is inversely proportional to species mass. Although other aspects can affect diffusive flux in a lithium ion battery, such as concentration and electric field (Nernst-Planck equation), with all other things being equal, the decreased ion mass of  6 Li results in a higher ionic flux as compared to that of  7 Li. Thus, the diffusion of the charge carrying species,  6 Li, will be higher than a comparable  7 Li ion. 
       FIG. 1  is a block diagram illustrating a battery  100 , according to an embodiment of the present invention. In this embodiment, the separator and electrolyte are replaced with specific  6 Li-based material. For example, the  6 Li-based material may also be composed of lithium-6 aluminum titanium phosphate (LATP), lithium-6 phosphorous oxynitride (LiPON), lithium-6 super ion conductor (LISICON, Li 2+2x Zn 1-x GeO 4 ), lithium-6 lanthanum zirconium oxide (LLZO), or other lithium ion transporting material synthesized from  6 Li precursors. In certain embodiments, however, a conventional separator and a conventional electrolyte liquid phase may be used provided that the salt is replaced with  6 Li. For example, the liquid phase may be composed of lithium-6 hexafluorophosphate ( 6 LiPF 6 ), lithium-6 perchlorate ( 6 LiClO 4 ), lithium-6 tetrafluoroborate ( 6 LiBF 4 ), and other conventional electrolyte salt  6 Li analogues. 
     The cathode, when synthesized, may be composed of materials using  6 Li. In  FIG. 1 , for example, the cathode may be composed of lithium-6 cobalt oxide ( 6 LCO), however, other  6 Li cathode materials may be used, such as lithium-6 manganese nickel oxide ( 6 LMNO), lithium-6 iron phosphate ( 6 LFP), lithium-6 nickel manganese cobalt oxide ( 6 NMC), lithium-6 manganese oxide ( 6 LMO), or other conventual cathode analogues synthesized using  6 Li precursors. The anode may also be synthesized from  6 Li materials. For example, the anode may be composed of lithium-6 metal ( 6 Li(s)), lithium-6 titanite ( 6 Li 2 TiO 3 ), or other conventional anode analogues synthesized using  6 Li precursors. 
     As briefly discussed above, state of the art lithium ion battery designs use natural abundance lithium, a mix of lithium-6 and lithium-7, but predominantly lithium-7, to the point where the physical and electrochemical properties of the battery are determined by the lithium-7 components. The small amount of  6 Li present in natural abundance lithium materials means that the electrochemical properties of batteries made using natural abundance lithium will be that of the dominant  7 Li. The electrochemical properties are ensemble properties, and all effects are proportional to the individual lithium populations. Use of the  6 Li isotope can apply to both conventional and novel lithium ion battery manufacturing. Conventional manufacturing of a lithium-6 based lithium ion battery may encompass prismatic assembly or cylindrically rolled assembly of cathode, anode, and separator with introduction of a liquid electrolyte. These materials can contain isotopically pure or enriched  6 Li, but otherwise use conventional battery assembly and design features and processes. This novel lithium ion battery assembly may also encompass evaporation of lithium-6 metal onto a current collector, physical vapor deposition of lithium-6-based ceramic solid electrolytes or cathode materials, or chemical vapor deposition or UV curing of lithium-6-based solid polymer electrolytes. 
       FIG. 2A  is a diagram illustrating a battery  200 A having a plurality of layers with  6 Li and  7 Li, according to an embodiment of the present invention. In this embodiment, a plurality of layers  202  are shown for both the anode and cathode. These layers  202  are the chemical layers of the material, with the atoms existing in sheets. 
     Battery  200 A using a mixture of lithium-6 and lithium-7 will have properties based on the proportional mix of the two species. As shown in  FIG. 2A , during intercalation into the solid planes of a lithium ion battery material, lithium-6 diffuses into the material faster and farther than lithium-7 does under electric fields and diffusion gradients. Thus, lithium-6 batteries will supply higher energy and power in lower temperatures, which is an important consideration for both conventional and solid-state lithium ion batteries. In addition, because of its lower mass,  6 Li will impart less mechanical stress during intercalation into, and deintercalation from, electrodes. By increasing the speed of diffusion, the  6 Li battery operates at a higher power than a conventional battery. By increasing the depth of diffusion in a given time,  6 Li requires less overpotential for intercalation, and thus a  6 Li battery operates more efficiently than a conventional lithium battery. 
       FIG. 2B  shows a  6 Li battery, with the replacement of the more massive  7 Li with  6 Li. This may result in further intercalation of lithium ions for the same electromotive force. The less massive  6 Li allows for the battery to operate at a higher power level. The specific capacity for one mole of naturally abundant lithium (6.941 g/mol) is 3860 mAh/g. In comparison, the specific capacity for one mole of  6 Li (6.015 g/mol) is 4454 mAh/g; assuming similar operating voltages, temperatures, and C-rates when implemented into lithium ion batteries, the higher specific energy/capacity of lithium-6 allow for higher operating powers and less massive batteries. In addition,  6 Li causes less physical and mechanical stress on the intercalation material, extending the life of the battery. 
     It will be readily understood that the components of various embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the detailed description of the embodiments of the present invention, as represented in the attached figures, is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. 
     The features, structures, or characteristics of the invention described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, reference throughout this specification to “certain embodiments,” “some embodiments,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in certain embodiments,” “in some embodiment,” “in other embodiments,” or similar language throughout this specification do not necessarily all refer to the same group of embodiments and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
     It should be noted that reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment. 
     Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention can be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention. 
     One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. In order to determine the metes and bounds of the invention, therefore, reference should be made to the appended claims.