Molten-salt batteriesare a class ofbatterythat usesmolten saltsas anelectrolyteand offers both a highenergy densityand a highpower density.Traditional non-rechargeablethermal batteriescan be stored in their solid state at room temperature for long periods of time before being activated by heating. Rechargeableliquid-metal batteriesare used for industrial power backup, specialelectric vehicles[citation needed]and forgrid energy storage,to balance out intermittentrenewable powersources such assolar panelsandwind turbines.
In 2023, the use of molten salts as electrolytes for high-energy rechargeable lithium metal batteries was demonstrated.[1][2]
History
editThermal batteries originated duringWorld War IIwhen German scientist Georg Otto Erb developed the first practical cells using a salt mixture as an electrolyte. Erb developed batteries for military applications, including theV-1 flying bomband theV-2rocket, and artillery fuzing systems. None of these batteries entered field use during the war. Afterwards, Erb was interrogated by British intelligence. His work was reported in "The Theory and Practice of Thermal Cells". This information was subsequently passed on to the United States Ordnance Development Division of theNational Bureau of Standards.[3]When the technology reached theUnited Statesin 1946, it was immediately applied to replacing the troublesome liquid-based systems that had previously been used to power artilleryproximity fuzes.They were used forordnanceapplications (e.g., proximity fuzes) since WWII and later innuclear weapons.The same technology was studied byArgonne National Laboratories[4]and other researchers in the 1980s for use inelectric vehicles.[5]
Rechargeable configurations
editSince the mid-1960s much development work has been undertaken onrechargeable batteriesusingsodium(Na) for the negative electrodes. Sodium is attractive because of its highreduction potentialof −2.71 volts, low weight, relative abundance, and low cost. In order to construct practical batteries, the sodium must be in liquid form. Themelting pointof sodium is 98 °C (208 °F). This means that sodium-based batteries operate at temperatures between 245 and 350 °C (470 and 660 °F).[6]Research has investigated metal combinations with operating temperatures at 200 °C (390 °F) and room temperature.[7]
Sodium–sulfur
editThesodium–sulfur battery(NaS battery), along with the relatedlithium–sulfur batteryemploys cheap and abundant electrode materials. It was the firstalkali-metalcommercial battery. It used liquidsulfurfor the positive electrode and aceramictube ofbeta-alumina solid electrolyte(BASE). Insulator corrosion was a problem because they gradually became conductive, and the self-discharge rate increased.
Because of their high specific power, NaS batteries have been proposed for space applications.[8][9]An NaS battery for space use was successfully tested on theSpace ShuttlemissionSTS-87in 1997,[10]but the batteries have not been used operationally in space. NaS batteries have been proposed for use in the high-temperature environment ofVenus.[10]
A consortium formed byTokyo Electric Power Co.(TEPCO) and NGK Insulators Ltd. declared their interest in researching the NaS battery in 1983, and became the primary drivers behind the development of this type ever since. TEPCO chose the NaS battery because its component elements (sodium, sulfur and ceramics) are abundant in Japan. The first large-scale field testing took place at TEPCO's Tsunashima substation between 1993 and 1996, using 3 × 2 MW, 6.6 kV battery banks. Based on the findings from this trial, improved battery modules were developed and were made commercially available in 2000. The commercial NaS battery bank offers:
- Capacity: 25–250 kWh per bank
- Efficiency of 87%
- Lifetime of 2,500 cycles at 100% depth of discharge (DOD), or 4,500 cycles at 80% DOD
Sodium–nickel chloride (Zebra) battery
editA lower-temperature[11]variant of molten-salt batteries was the development of the ZEBRA (originally, "Zeolite Battery Research Africa"; later, the "Zero Emissions Batteries Research Activity" ) battery in 1985, originally developed for electric vehicle applications.[12][13]The battery usesNaNiCl
2with Na+-beta-alumina ceramic electrolyte.[14]
TheNaNiCl
2battery operates at 245 °C (473 °F) and uses moltensodium tetrachloroaluminate(NaAlCl
4), which has a melting point of 157 °C (315 °F), as the electrolyte. The negative electrode is molten sodium. The positive electrode isnickelin the discharged state andnickel chloridein the charged state. Because nickel and nickel chloride are nearly insoluble in neutral andbasicmelts, contact is allowed, providing little resistance to charge transfer. Since bothNaAlCl
4and Na are liquid at the operating temperature, a sodium-conductingβ-alumina ceramicis used to separate the liquid sodium from the moltenNaAlCl
4.The primary elements used in the manufacture of these batteries have much higher worldwide reserves and annual production than lithium.[15]
It was invented in 1985 by the Zeolite Battery Research Africa Project (ZEBRA) group at theCouncil for Scientific and Industrial Research (CSIR)inPretoria, South Africa.It can be assembled in the discharged state, using NaCl, Al, nickel and iron powder. The positive electrode is composed mostly of materials in the solid state, which reduces the likelihood of corrosion, improving safety.[16]Itsspecific energyis 100 Wh/kg; specific power is 150 W/kg. The β-alumina solid ceramic is unreactive to sodium metal and sodium aluminum chloride. Lifetimes of over 2,000 cycles and twenty years have been demonstrated with full-sized batteries, and over 4,500 cycles and fifteen years with 10- and 20-cell modules. For comparison,[citation needed]LiFePO4lithium iron phosphate batteriesstore 90–110 Wh/kg, and the more commonLiCoO2lithium-ionbatteries store 150–200 Wh/kg. A nanolithium-titanate batterystores 72 Wh/kg and can provide power of 760 W/kg.[17]
The ZEBRA's liquid electrolyte freezes at 157 °C (315 °F), and the normal operating temperature range is 270–350 °C (520–660 °F). Adding iron to the cell increases its power response.[16]ZEBRA batteries are currently manufactured by FZSoNick[18]and used as a power backup in the telecommunication industries, Oil&Gas and Railways. It is also used in special electric vehicles used in mining. In the past it was adopted in theModecElectric Van,[citation needed]theIveco Daily3.5-ton delivery vehicle,[citation needed]the prototypeSmart ED,and theTh!nk City.[19]In 2011 the US Postal Service began testing all-electric delivery vans, one powered by a ZEBRA battery.[20]
In 2010General Electricannounced aNa-NiCl
2battery that it called a sodium–metal halide battery, with a 20-year lifetime. Its cathode structure consists of a conductive nickel network, molten salt electrolyte, metal current collector, carbon felt electrolyte reservoir and the active sodium–metal halide salts.[21][22]In 2015, as a result of a global restructuring, the company abandoned the project.[23]In 2017 Chinese battery maker Chilwee Group (also known as Chaowei) created a new company with General Electric (GE) to bring to market a Na-NiCl battery for industrial and energy storage applications.[24]
When not in use,Na-NiCl
2batteries are typically kept molten and ready for use because if allowed to solidify they typically take twelve hours to reheat and charge.[25]This reheating time varies depending on the battery-pack temperature, and power available for reheating. After shutdown a fully charged battery pack loses enough energy to cool and solidify in five-to-seven days depending on the amount of insulation.[citation needed]
Sodium metal chloride batteries are very safe; athermal runawaycan be activated only by piercing the battery and also, in this unlikely event, no fire or explosion will be generated. For this reason and also for the possibility to be installed outdoor without cooling systems, make the sodium metal chloride batteries very suitable for the industrial and commercial energy storage installations.
Sumitomostudied a battery using a salt that is molten at 61 °C (142 °F), far lower than sodium based batteries, and operational at 90 °C (194 °F). It offers energy densities as high as 290 Wh/L and 224 Wh/kg and charge/discharge rates of 1C with a lifetime of 100–1000 charge cycles. The battery employs only nonflammable materials and neither ignites on contact with air nor risks thermal runaway. This eliminates waste-heat storage or fire- and explosion-proof equipment, and allows closer cell packing. The company claimed that the battery required half the volume of lithium-ion batteries and one quarter that of sodium–sulfur batteries.[26]The cell used a nickel cathode and a glassy carbon anode.[27]
In 2014 researchers identified a liquid sodium–cesium alloy that operates at 50 °C (122 °F) and produced 420 milliampere-hours per gram. The new material was able to fully coat, or "wet," the electrolyte. After 100 charge/discharge cycles, a test battery maintained about 97% of its initial storage capacity. The lower operating temperature allowed the use of a less-expensive polymer external casing instead of steel, offsetting some of the increased cost of cesium.[28]
Innovenergy inMeiringen,Switzerlandhas further optimised this technology with the use of domestically sourced raw materials, except for the nickel powder component. Despite the reduced capacity compared withlithium-ion batteries,the ZEBRA technology is applicable forstationary energy storagefromsolar power.In 2022, the company operated a 540 kWh storage facility for solar cells on the roof of a shopping center, and currently produces over a million battery units per year from sustainable, non-toxic materials (table salt).[29]
Liquid-metal batteries
editProfessorDonald Sadowayat the Massachusetts Institute of Technology has pioneered the research of liquid-metal rechargeable batteries, using both magnesium–antimony and more recentlylead–antimony.The electrode and electrolyte layers are heated until they are liquid and self-segregate due to density andimmiscibility.Such batteries may have longer lifetimes than conventional batteries, as the electrodes go through a cycle of creation and destruction during the charge–discharge cycle, which makes them immune to the degradation that afflicts conventional battery electrodes.[30]
The technology was proposed in 2009 based onmagnesiumandantimonyseparated by a molten salt.[31][32][33]Magnesium was chosen as the negative electrode for its low cost and low solubility in the molten-salt electrolyte. Antimony was selected as the positive electrode due to its low cost and higher anticipated discharge voltage.
In 2011, the researchers demonstrated a cell with a lithium anode and a lead–antimony cathode, which had higher ionic conductivity and lower melting points (350–430 °C).[30]The drawback of the Li chemistry is higher cost. A Li/LiF + LiCl + LiI/Pb-Sb cell with about 0.9 V open-circuit potential operating at 450 °C had electroactive material costs of US$100/kWh and US$100/kW and a projected 25-year lifetime. Its discharge power at 1.1 A/cm2is only 44% (and 88% at 0.14 A/cm2).
Experimental data shows 69% storage efficiency, with good storage capacity (over 1000 mAh/cm2), low leakage (< 1 mA/cm2) and high maximal discharge capacity (over 200 mA/cm2).[34]By October 2014 the MIT team achieved an operational efficiency of approximately 70% at high charge/discharge rates (275 mA/cm2), similar to that ofpumped-storage hydroelectricityand higher efficiencies at lower currents. Tests showed that after 10 years of regular use, the system would retain about 85% of its initial capacity.[35]In September 2014, a study described an arrangement using a molten alloy of lead and antimony for the positive electrode, liquid lithium for the negative electrode; and a molten mixture of lithium salts as the electrolyte.
A recent innovation is the PbBi alloy which enables lower melting point lithium-based battery. It uses a molten salt electrolyte based on LiCl-LiI and operates at 410 °C.[36]
Ionic liquidshave been shown to have prowess for use in rechargeable batteries. The electrolyte is pure molten salt with no added solvent, which is accomplished by using a salt having a room temperature liquid phase. This causes a highly viscous solution, and is typically made with structurally large salts with malleable lattice structures.[37]
Thermal batteries (non-rechargeable)
editTechnologies
editThermal batteries use an electrolyte that is solid and inactive at ambient temperatures. They can be stored indefinitely (over 50 years) yet provide full power in an instant when required. Once activated, they provide a burst of high power for a short period (a few tens of seconds to 60 minutes or more), with output ranging fromwattstokilowatts.The high power is due to the highionic conductivityof the molten salt (resulting in a low internal resistance), which is three orders of magnitude (or more) greater than that of thesulfuric acidin alead–acid car battery.
One design uses a fuze strip (containingbarium chromateand powderedzirconiummetal in a ceramic paper) along the edge of the heat pellets to initiate the electrochemical reaction. The fuze strip is typically fired by anelectrical igniterorsquibwhich is activated with an electric current.
Another design uses a central hole in the middle of the battery stack, into which the high-energy electrical igniter fires a mixture of hot gases andincandescentparticles. This allows much shorter activation times (tens of milliseconds) vs. hundreds of milliseconds for the edge-strip design. Battery activation can be accomplished by apercussion primer,similar to ashotgun shell.The heat source should be gasless. The standard heat source typically consists of mixtures ofironpowder andpotassium perchloratein weight ratios of 88/12, 86/14, or 84/16.[38]The higher the potassium perchlorate level, the higher the heat output (nominally 200, 259, and 297cal/grespectively). This property of unactivated storage has the double benefit of avoiding deterioration of the active materials during storage and eliminating capacity loss due toself-dischargeuntil the battery is activated.
In the 1980slithium-alloy anodes replacedcalciumormagnesiumanodes, with cathodes ofcalcium chromate,vanadiumortungsten oxides.Lithium–siliconalloys are favored over the earlier lithium–aluminium alloys. The corresponding cathode for use with the lithium-alloy anodes is mainlyiron disulfide(pyrite) replaced by cobalt disulfide for high-power applications. The electrolyte is normally aeutectic mixtureoflithium chlorideandpotassium chloride.
More recently, other lower-melting, eutectic electrolytes based onlithium bromide,potassium bromide,and lithium chloride orlithium fluoridehave also been used to provide longer operational lifetimes; they are also better conductors. The so-called "all-lithium" electrolyte based onlithium chloride,lithium bromide,andlithium fluoride(no potassium salts) is also used for high-power applications, because of its high ionic conductivity. Aradioisotope thermal generator,such as in the form of pellets of90SrTiO4,can be used for long-term delivery of heat for the battery after activation, keeping it in a molten state.[39]
Uses
editThermal batteries are used almost exclusively for military applications, notably for nuclear weapons[40]andguided missiles.[41][unreliable source?][42][unreliable source?]They are the primary power source for many missiles such as theAIM-9 Sidewinder,AIM-54 Phoenix,MIM-104 Patriot,BGM-71 TOW,BGM-109 Tomahawkand others. In these batteries the electrolyte is immobilized when molten by a special grade ofmagnesium oxidethat holds it in place bycapillary action.This powdered mixture is pressed intopelletsto form a separator between theanodeandcathodeof each cell in the battery stack. As long as the electrolyte (salt) is solid, the battery is inert and remains inactive. Each cell also contains apyrotechnic heat source,which is used to heat the cell to the typical operating temperature of 400–550 °C.
See also
editReferences
edit- ^Phan, An L; Jayawardana, Chamithri; Le, Phung ML; Zhang, Jiaxun; Nan, Bo; Zhang, Weiran; Lucht, Brett L; Hou, Singyuk; Wang, Chunsheng (August 2023)."Solvent-Free Electrolyte for High-Temperature Rechargeable Lithium Metal Batteries".Advanced Functional Materials.33(34).doi:10.1002/adfm.202301177.hdl:1903/30697.ISSN1616-301X.
- ^Vu, Minh Canh; Mirmira, Priyadarshini; Gomes, Reginaldo J.; Ma, Peiyuan; Doyle, Emily S.; Srinivasan, Hrishikesh S.; Amanchukwu, Chibueze V. (December 2023)."Low melting alkali-based molten salt electrolytes for solvent-free lithium-metal batteries".Matter.6(12):4357–4375.doi:10.1016/j.matt.2023.10.017.ISSN2590-2385.
- ^9th Intersociety Energy Conversion Engineering Conference Proceedings.American Society of Mechanical Engineers. 1974. p. 665.
- ^A. E. Martin, in "High Performance Batteries for Electric Vehicles Propulsion and Stationary Energy Storage",Argonne National LaboratoriesReport ANL-78-94 (1980); and Report ANL-79-39 (1979).
- ^T.M. O'Sullivan, C.M. Bingham, and R.E. Clark, "Zebra battery technologies for all electric smart car",International Symposium on Power Electronics, Electrical Drives, Automation and Motion, SPEEDAM 2006, IEEE, 23–26 May 2006. Retrieved 12 June 2018
- ^Buchmann, Isidor (August 2011)."Weird and Wonderful Batteries: But Will the Inventions Survive Outside the Laboratory?".Batteries in a Portable World.Retrieved30 November2014.
- ^Ding, Yu; Guo, Xuelin; Yu, Guihua (26 August 2020)."Next-Generation Liquid Metal Batteries Based on the Chemistry of Fusible Alloys".ACS Central Science.6(8):1355–1366.doi:10.1021/acscentsci.0c00749.PMC7453561.PMID32875076.
Intermediate and room-temperature liquid metal batteries, circumventing complex thermal management as well as issues related to sealing and corrosion, are emerging as a novel energy system for widespread implementation
- ^Koenig, A.A; Rasmussen, J.R (1990). "Development of a high specific power sodium sulfur cell".Proceedings of the 34th International Power Sources Symposium.pp.30–33.doi:10.1109/IPSS.1990.145783.ISBN978-0-87942-604-0.S2CID111022668.
- ^Auxer, William (1986-01-01).The PB sodium sulfur cell for satellite battery applications.32nd International Power Sources Symposium(Report). pp.49–54.Bibcode:1986poso.symp...49A.
- ^abLandis, Geoffrey A; Harrison, Rachel (2010). "Batteries for Venus Surface Operation".Journal of Propulsion and Power.26(4):649–654.doi:10.2514/1.41886.
- ^Li, Guosheng; Lu, Xiaochuan; Kim, Jin Y.; Meinhardt, Kerry D.; Chang, Hee Jung; Canfield, Nathan L.; Sprenkle, Vincent L. (11 February 2016)."Advanced intermediate temperature sodium–nickel chloride batteries with ultra-high energy density".Nature Communications.7:10683.Bibcode:2016NatCo...710683L.doi:10.1038/ncomms10683.PMC4753253.PMID26864635.
- ^7.6 The Sodium Nickel Chloride "Zebra" Battery,Meridian International Research, 2006, p. 104-112. Accessed 2 August 2017.
- ^Sudworth, J.L. (August 1994). "Zebra batteries".Journal of Power Sources.51(1–2):105–114.Bibcode:1994JPS....51..105S.doi:10.1016/0378-7753(94)01967-3.
- ^Shukla, A. K.; Martha, S. K. (July 2001). "Electrochemical power sources".Resonance.6(7):52–63.doi:10.1007/BF02835270.S2CID109869429.
- ^William Tahil, Research Director (December 2006)."The Trouble with Lithium, Implications of Future PHEV Production for Lithium Demand"(PDF).Meridian International Research. Archived fromthe original(PDF)on 2009-02-22.Retrieved2009-02-28.
- ^abEllis, Brian L.; Nazar, Linda F. (2012)."Sodium and sodium-ion energy storage batteries"(PDF).Current Opinion in Solid State and Materials Science.16(4):168–177.Bibcode:2012COSSM..16..168E.doi:10.1016/j.cossms.2012.04.002.Archived fromthe original(PDF)on 2014-12-10.Retrieved2014-12-06.
- ^Lithium-titanate datasheet.
- ^"THE SALT BATTERY".fzsonick.Archived fromthe originalon December 4, 2013.
- ^"Think Global web site".Archived fromthe originalon August 19, 2009.
- ^"Idaho National Labs spec sheet"(PDF).Archived fromthe original(PDF)on 2012-04-29.Retrieved2011-11-11.
- ^"GE Launches Durathon Sodium–Metal Halide Battery for UPS Market".Green Car Congress. 2010-05-18.Retrieved2012-04-24.
- ^"GE to Manufacture Molten Salt Sodium Nickel Chloride Batteries for Stationary Electricity Storage Applications".
- ^"GE Reboots Its Storage Business With a Lithium-Ion Battery and Downstream Services".2015-04-28.
- ^"Joint Venture to bring sodium nickel battery to market | bestmag.co.uk".bestmag.co.uk.6 January 2017.
- ^Jung, Keeyoung (ORCID:0000000233322335); Chang, Hee-Jung; Bonnett, Jeffery F.; Canfield, Nathan L.; Sprenkle, Vincent L.; Li, Guosheng (June 14, 2018)."An advanced Na-NiCl2 battery using bi-layer (dense/micro-porous) β" -alumina solid-state electrolytes ".Journal of Power Sources.396(C).doi:10.1016/J.JPOWSOUR.2018.06.039.S2CID102547122– via osti.gov.
{{cite journal}}
:CS1 maint: numeric names: authors list (link) - ^"Sumitomo considering marketing new lower-temperature molten-salt electrolyte battery to automakers for EVs and hybrids".Green Car Congress. 2011-11-11.Retrieved2012-04-24.
- ^Koji NITTA; Shinji INAZAWA; Shoichiro SAKAI; Atsushi FUKUNAGA; Eiko ITANI; Kouma NUMATA; Rika HAGIWARA & Toshiyuki NOHIRA (April 2013)."Development of Molten Salt Electrolyte Battery"(PDF).SEI TECHNICAL REVIEW.
- ^Lu, Xiaochuan; Li, Guosheng; Kim, Jin Y.; Mei, Donghai; Lemmon, John P.; Sprenkle, Vincent L.; Liu, Jun (1 August 2014)."Liquid-metal electrode to enable ultra-low temperature sodium–beta alumina batteries for renewable energy storage".Nature Communications.5(1): 4578.Bibcode:2014NatCo...5.4578L.doi:10.1038/ncomms5578.PMID25081362.
- ^Innovenergy, SRF Report on "Salt Batteries" (in German).innov.energy.de.Retrieved 4 February 2022.
- ^abKim, Hojong; Boysen, Dane A; Newhouse, Jocelyn M; Spatocco, Brian L; Chung, Brice; Burke, Paul J; Bradwell, David J; Jiang, Kai; Tomaszowska, Alina A; Wang, Kangli; Wei, Weifeng; Ortiz, Luis A; Barriga, Salvador A; Poizeau, Sophie M; Sadoway, Donald R (2012). "Liquid Metal Batteries: Past, Present, and Future".Chemical Reviews.113(3):2075–2099.doi:10.1021/cr300205k.PMID23186356.("Archived copy"(PDF).Archived fromthe original(PDF)on 2019-01-22.Retrieved2021-09-02.
{{cite web}}
:CS1 maint: archived copy as title (link)) - ^Staff (2012)Ambri TechnologyAmbri company web page, Retrieved 6 December 2012.
- ^David L. Chandler, MIT News Office (19 November 2009)."Liquid battery big enough for the electric grid?".MIT News.
- ^US20110014503 0
- ^Bradwell, David J; Kim, Hojong; Sirk, Aislinn H. C; Sadoway, Donald R (2012)."Magnesium–Antimony Liquid Metal Battery for Stationary Energy Storage"(PDF).Journal of the American Chemical Society.134(4):1895–1897.Bibcode:2012JAChS.134.1895B.CiteSeerX10.1.1.646.1667.doi:10.1021/ja209759s.PMID22224420.
- ^Wang, Kangli; Jiang, Kai; Chung, Brice; Ouchi, Takanari; Burke, Paul J; Boysen, Dane A; Bradwell, David J; Kim, Hojong; Muecke, Ulrich; Sadoway, Donald R (2014)."Lithium–antimony–lead liquid metal battery for grid-level energy storage".Nature.514(7522):348–350.Bibcode:2014Natur.514..348W.doi:10.1038/nature13700.PMID25252975.S2CID848147.
- ^Kim, Junsoo; Shin, Donghyeok; Jung, Youngjae; Hwang, Soo Min; Song, Taeseup; Kim, Youngsik; Paik, Ungyu (2018). "LiCl-LiI molten salt electrolyte with bismuth-lead positive electrode for liquid metal battery ".Journal of Power Sources.377:87–92.Bibcode:2018JPS...377...87K.doi:10.1016/j.jpowsour.2017.11.081.
- ^Giffin, Guinevere A. (August 30, 2016)."Ionic liquid-based electrolytes for" beyond lithium "battery technologies".Journal of Materials Chemistry A.4(35):13378–13389.doi:10.1039/C6TA05260F– via pubs.rsc.org.
- ^Koch, E.-C. (2019)."Special Materials in Pyrotechnics, VII: Pyrotechnics used in thermal batteries".Def. Tech.15(3):254–263.doi:10.1016/j.dt.2019.02.004.
- ^"Isotope heated deferred action thermal batteries – Catalyst Research Corporation".Freepatentsonline.Retrieved2012-04-24.
- ^Always/Never: The Quest for Safety, Control, and Survivability - Part 2,15 June 2015,retrieved2022-09-22
- ^"ASB Group – Military Thermal Batteries".Army Technology. 2011-06-15.Retrieved2012-04-24.
- ^"EaglePicher – Batteries and Energetic Devices".Naval Technology. 2011-06-15.Retrieved2012-04-24.