​Lithium Carbonate in Lithium-Ion Battery Applications.

Lithium-ion batteries are known as those rechargeable batteries where lithium ions work through transmitting from the negative to the positive electrode. These are one of the most used batteries in today’s world as they are being used for so many different purposes owing to the excellent features that they bring forth. Lithium carbonate is a white salt that works as an inorganic compound with a mixture of lithium, carbon, and oxygen.

Lithium-ion batteries become much more powerful and active with the incorporation of lithium carbonate in them as it enhances the production and applications of these batteries. 

Introduction

A Li-ion battery or lithium-ion battery is a rechargeable battery type in which the lithium ions move through an electrolyte during discharge and charge, from the negative electrode to the positive electrode. Graphite is typically used at the negative electrode by the Li-ion batteries and an intercalated lithium compound is used as the material at the positive electrode by the Lithium-ion batteries.

High energy density

Low self-discharge, no memory effect (except LFP cells), and high energy density are possessed by the Li-ion batteries. The manufacturing of cells is done for either prioritizing power density or energy. Although, they can be a hazard as flammable electrolytes are possessed by them and they can result in fires and explosions if charged incorrectly or damaged.

Development of Lithium-ion battery

In 1985, Akira Yoshino made aprototype Lithium-ion battery, based on the research that was done earlier during the 1970s-1980s by Koichi Mizushima, Rachid Yazami, M. Stanley Whittingham, and John Goodenough, and then in 1991, Yoshio Nishi led the team of Asahi Kasei and Sony and developed a commercial lithium-ion battery. Li-ion batteries are getting famous for aerospace and military applications. They are utilized commonly for electric vehicles and portable electronics.

Characteristics

Different types of Li-ion batteries have different safety characteristics, cost, performance, and chemistry. A graphite anode, a lithium cobalt oxide (LiCoO2) cathode material, and lithium polymer batteries (with polymer gel as electrolyte), are mostly used by handheld electronics, which combined provide a high energy density. Better rate capability and longer lives are offered by lithium nickel manganese cobalt oxide (NMC or LiNiMnCoO2), lithium manganese oxide (LMR-NMC, LiMn2O4 spinel, or Li2MnO3-based lithium-rich layered materials), and lithium iron phosphate (LiFePO4). Such batteries are utilized broadly for medical equipment, electric tools, and other roles. There is a wide usage of NMC and its derivatives in electric vehicles.

More areas of research for lithium-ion batteries

Increased speed of charging, lessening cost, enhancing safety, increasing energy density, and extended lifetime, among others, are the areas of research for lithium-ion batteries. There has been research in progress in the area of the non-flammable electrolyte as a method for increasing safety based on the organic solvent's volatility and flammability that are utilized in a normal electrolyte. Methods include heavily fluorinated systems, ionic liquids, polymer electrolytes, ceramic solid electrolytes, and aqueous lithium-ion batteries.

Present Day Li-Ion Batteries

As compared to the real small electronic devices for the 3C market that is mentioned above, the current lithium-ion batteries market is way more complicated. Various markets have been started for small devices like medical devices, vaporizers, e-cigarettes, lighting (fluorescent lights and LCD), and toys. The discovery that the Li-ion battery packs utilizing 26650, 26700, and 18650 sizes can be made for functioning at way higher power as compared to what was originally suspected, has opened markets for e-bikes, garden tools, portable electric tools, and various other products.

High energy cells

Some capacity has already been sacrificed by some of the high power cells for achieving 20A or more continuous discharge capability in the cell size of 18650, whereas now 3.4 Ah or more is possessed by high energy 18650 cells. Sustaining a high capacity during cycling is difficult even though some cells have as high as the capacity of 2.5 Ah. Spotnitz, Reimers, and coworkers did modeling studies that clearly showed the significant effect of tab placement and multiple tabs. Carbon type that is utilized in the negative electrode, electrode's porosities, positive electrode’s carbon content, and thickness of the electrode are other major design variables.

Development of ceramic coatings

Moreover, it is because of the metal particle's adventitious presence on the electrode's surface that the production of ceramic coatings to the positive electrode or the separator has had an advantageous effect on the prevention of internal short-circuiting while cycling. Generally, these particles are airborne and small and they usually result from the electrode's mechanical slitting. The separator's thickness is only 12-25 μm. This thickness proves that the concept of extremely small conductive particles penetrating the separator, causing a short, is a significant failure mechanism of the Li-ion batteries. Such separator coatings can be as thin as the thickness of 2 micrometers. They can be on one or both of the sides of the polyolefin separator.

Additional benefits

Separator's coating has other additional benefits, which include enhanced electrolyte wetting due to the easily wet inorganic oxide ceramic phase, better cycling if, during cycling, a weak short circuit degrades capacity without making any safety incident, and separator's much-lessened shrinkage at the shutdown temperatures (current's shutdown because the melting of the separator may not succeed if the shrinking reaches to an extent that the direct contact between the cathode and anode is permitted). Now, more difficult coatings are turning common, for instance, Panasonic and Tesla motors used the Sumitomo separator which involves coating with aromatic polyamide (aramid polymer) and also ceramic particles for increasing the coating's strength of penetration.

Present cathode materials

LiMn2O4 (LMO) and the original LiCoO2 (LCO) are included in the cathode materials that are in common usage currently. LiNixMnyCo1-x-yO2 is another excellent material that’s still under development. Generally, It is known as NMC. Usually, the subscripts are known by their atomic ratios like 811, 442, or 532 (other than the x = y = 1/3 which was investigated initially and known as 111 or 333). 532 and 111 are the most usually utilized materials.

Competitive materials

Moreover, LiNi0.80Co0.15Al0.05 (NCA) is an extremely competitive material, also a layered R3-m structure. Several groups competitively made a more recent material, known as LiFePO4 (LFP) with a 1-dimensional tunnel structure. Each material has some particular disadvantages and advantages and they have been implemented in various applications.

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Lithium carbonate

With Li₂CO₃ formula, the lithium salt of carbonate, it is an inorganic compound. It is utilized in a broad range as a drug to treat numerous mood disorders and in processing metal oxides.

Reactions and Characteristics

The existence of lithium carbonate takes place only in the anhydrous form, unlike sodium carbonate, which produces 3 hydrates at least. As compared to the other lithium salts, it has low solubility in water. Lithium's isolation from lithium ores' aqueous extracts capitalizes on this poor solubility in water. Under carbon dioxide's mild pressure, there comes a 10-fold increase in its apparent solubility. This effect is because the production of the metastable bicarbonate and metastable bicarbonate is more soluble.

Li2CO3 + CO2 + H2O ⇌ 2 LiHCO3

Extraction of lithium carbonate

Quebec process’s basis is lithium carbonate’s extraction at CO2’s high pressures and its precipitation on depressurizing. The exploitation of lithium carbonate's diminished solubility in hot water can purify lithium carbonate. Therefore, Li2CO3’s crystallization can be caused by heating the saturated aqueous solution. Group 1’s lithium carbonate and other carbonates do not readily decarboxylate. The decomposition of Li2CO3 occurs at 1300 degrees Celsius of temperatures.

Lithium carbonate’s usages

Lithium carbonate is a significant industrial chemical. The main usage for lithium carbonate is as a precursor in the Li-ion batteries. There are plenty of usages of the glass produced from lithium carbonate in the ovenware. In both high-fire and low-fire ceramic glaze, the ingredient that’s commonly used is lithium carbonate. Lithium carbonate produces low-melting fluxes with other materials and silica. Its alkaline characteristics are conductive for altering the metal oxide colorants state in glaze, red iron oxide (Fe2O3) specifically. When they are made with lithium carbonate, cement is set more fastly, and cement is beneficial for the tile adhesives. It produces LiF when added to the aluminumtrifluoride, and it gave a superior electrolyte to process aluminum.

Rechargeable batteries

Lithium carbonate’s main usage is as a precursor to the lithium compounds that are utilized in the Li-ion batteries. Practically, lithium compounds are used to make two components of the battery; the electrolyte and the cathode. One of the various lithiated structures are used by the cathode, lithium iron phosphate and lithium cobalt oxide are among the most popular, whereas the electrolyte is lithium hexafluorophosphate’s solution. Before being converted into the compounds that are mentioned above, lithium carbonate may convert first into lithium hydroxide.

Lithium Carbonate in Li-Ion Battery Applications

Li2CO3 production from the concentrated lithium brine

They took concentrated lithium brine in trucks to 232 km for refinement and processing from Salar de Atacama to Antofagasta, Chile. A payload of 24.5 tonnes is carried by each truck. Boron is eliminated from brine at the Li2CO3 production plant and then goes through purification and carbonation according to Steinbild and Wietelmann.

Boron extraction facility

An organic solvent, sulfuric acid (H2SO4), alcohol, and hydrogen chloride (HCl) are consumed by the boron extraction facility. At the extraction phase, lime (CaO) and soda ash (Na2CO3) is added to the treated lithium brine for removing magnesium. Li2CO3 is yielded as a solid by a precipitation reaction for which soda ash is combined with purified brine. Before its compaction and packaging, the end product is dried after being washed and filtered.

Material’s total consumption

Total water, energy, and material used for producing Li2CO3 were determined by using the producer data. As there is no need for the process-level analysis and a single product —Li2CO3— is produced by this facility that’s why the whole process of production of Li2CO3 is treated at the facility level. Particulate matter emissions data were provided other than energy inputs, water, and material for the operation of the facility. Energy and material flow for the production of Li2CO3 from lithium brine. Water isn’t included in the LCL as despite being utilized in the process, it is not consumed and is a completely recycled stream.

Stages of lithium carbonate

LiOH•H2O is formed by the reaction of Li2CO3 in a series of stages with a mixture of water and CaO. There is still no need for process-level analysis as only LiOH•H2O is the product from the facility. At the facility level, data was analyzed and the material inputs and requisite energy were determined for the production of LiOH•H2O. There are 2 facilities for the production of LiOH•H2O and Li2CO3 at the same plant respectively but there is a separation of the facilities and there is unique data for the production of each.

Requirement of production

During the process of refining, auxiliary chemicals are required by the production of Li2CO3. CaO, organic solvent, alcohol, HCl, H2SO4, and soda ash are included in these, and they all are modeled in GREET. These resources’ default amounts of production and transportation are utilized in this analysis with an anticipated Chilean production basis. CaO is the exception, as its production is done in the US, and trucks and ships are used to transport it to Chile, with a distance of 200 and 5000 miles (322 and 8047 km). The utilization of this CaO proxy was for anonymization.

Various allocation approaches

In China, the stage of carbonate production is extremely energy expensive. As compared to the 4 Chilean allocation methods, it performs worse. Also, a meaningful influence is possessed by Na2CO3 input on energy usage. It should be noted that the transit stage is for the analyzed product’s transit only. Here, Li2CO3 is the analyzed product. As compared to the brine-based pathway, the ore-based pathway functions worse.

Lithium carbonate’s concentration

The primary driver of GHG emissions for the brine-based pathways is Na2CO3 followed by the energy for the production of concentrated brine (determined by brine allocation approach) and Li2CO3. After spodumene concentrate, the main driver for the ore-based lithium is Li2CO3 production. Production of Li2CO3’s production in China is modeled on a facility which is utilizing coal for heat, and then transitioning it to natural gas which would most probably lessen the GHG emissions.

GHG emissions

The findings for Li2CO3’s brine-based formation are in consistency with the literature, whereas there are different GHG emission findings for the Li2CO3 that’s produced from the ore. According to Dunn et al.’s old work that was turned into GREET model, GHG emissions of 3.8 tonnes of CO2e per tonne of Li2CO3 from brine. According to Kendall and Ambrose, Li2CO3 that’s produced from brine leads to Li2CO3 of 3.06 tonnes of CO2e per tonne.

Differentiation in production

The production of Li2CO3’s synthesis from brine is different from the synthesis of Li2CO3 from ore. According to the findings of Ambrose and Kendall, ore-synthesized Li2CO3 makes 2.28 tonnes of CO2e per Li2CO3 of a tonne. New information is reflected in this study, identifying increases in carbon dioxide per tonne of Li2CO3, in the usage of Na2CO3, and in energy inputs for the formation of Li2CO3 itself.

Effect on battery system

We can see lithium production’s impact on the whole battery system. NMC811 and NMC622 cathode materials were examined to be used in the automotive battery. 241 Wh/kg is the NMC622 battery's specific energy based on Argonne's BatPac Model, whereas it's 248 Wh/kg for an NMC811 battery. The 300-mile range is achieved by both the batteries as they have an energy capacity of 84 kWh. 54 kg LiOH•H2O per battery kWh (0.09 kg Li per battery kWh) is contained by an NMC811 battery, whereas 0.57 kg Li2CO3 per battery kWh (0.11 kg Li per battery kWh) is contained by an NMC622 battery.

Inputs of battery materials

Argonne BatPac Model v4.0 was used to model the battery material inputs for both NMC811 AND NMC622 (Argonne National Laboratory 2020). In 2020, these batteries’ life cycle inventory details are described by Winjobi et al. for GREET integration. Here, those material's battery bills and details of energy usage are used along with the brief lithium production processes that were mentioned earlier for evaluating the impact that the various lithium sources have on the batteries’ life cycle (and allocation approaches). Again, GREET’s baseline settings are used for gathering the background data.

Connections in terms of lithium’s production

LCA was overall utilized for connecting lithium’s formation from ore or brine via formation of NMC811 and NMC622 cathode powder, formation of lithium compounds (LiOH•H2O and Li2CO3), and resource concentration, all the way through the utilization of lithium in NMC811 or NMC622 battery's form, in an electric vehicle. According to the analysis, the reported environmental effect is impacted by the resource allocation approach that's used and the lithium source matters (ore or brine) with respect to environmental effects. Those process-level LCA results are recommended by us as this analysis was capable of leveraging the process-level data for production based on the brine. They are recommended as they are most representative of water utilization, materials, and actual process energy in the formation of concentrated lithium brine.

Lithium Carbonate’s recovery

Sieving can easily separate the Al foil in the residue after the leaching of the formic acid. ICP-OES can be used to analyze each element's mass fraction in the Al foil where 99.98% is Al's mass fraction. The above-mentioned procedures were done to process the leach solution for carrying out the leftover Mn, Co, and Ni. Excessive (110%) saturated Na2CO3 is added to subsequently obtain lithium carbonate for achieving lithium carbonate. In water, Lithium carbonate is slightly soluble, and as the temperature increases, the solubility decreases.

XRD pattern

The achieved lithium carbonate’s XRD pattern agrees with the standard pattern peaks. Aqua regia further dissolved the precipitated Li2CO3 for calculating lithium carbonate’s purity accurately, and ICP-OES was used to measure its mass fraction of metals.

Lithium carbonate’s SEM images

The precipitated Li2CO3's SEM images show that the precipitated Li2CO3 was displayed as severe agglomerates of various primary sheets. According to findings, 10.64 ± 1.47 μm is the particle size distribution. After precipitation, 98.20% was Na+ mass fraction in the solution among the metallic ions, where HCOO— is the anion through the complete process of leaching. Then the solution can be processed further for the preparation of NaCOOH or utilized directly after the adjustment of pH for processing of leather, and the Ni-Co-Mn precipitates are ready for cathode materials’ precursor formation.

Developing New Lithium-Ion Battery Production Process

There was schematic plotting of a new Li-ion battery formation process under formic acid's leaching on previous experimental and theoretical result's basis. All the metals have global recovery rates of over 90 percent. Mainly, the cathode scrap's Mn, Co, and Ni were recovered in the residue solution with little loss as hydroxide precipitates (Ni−Co−Mn precipitates I and II). Around 0.005 wt percent of Ni-Co-Mn was lost as Al foil’s impurity in the process of separating Ni-Co-Mn precipitate Al and I foil.

Global recovery rates

99.96% were the Mn, Co, and Ni's global recovery rates in this process. In the complete recovery process, Al's product form is in its form of fool with 4.54 wt percent dissolved in the leaching process only. One can also identify Mn, Co, and Ni hydroxide precipitate’s XRD result in the precipitate. There is no identification of the Al(OH)3 phase. Also, according to findings, LiNi1/3Co1/3Mn1/3O2 cycle stability and rate performance can be increased with an enhanced lamellar structure with the help of even some AI quantity left in the precipitates, which may be present in the cathode materials.

Conclusion

With the incorporation of lithium carbonate in lithium-ion batteries, these batteries have massively increased in terms of production and applications due to the excellent features and characteristics that it brings along. However, ongoing and further research is needed to proclaim all the advantages that are provided by lithium carbonate to lithium-ion batteries in terms of enhancing their applications and products.

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References:

https://iopscience.iop.org/article/10.1149/2.0251701jes/pdf

https://www.sciencedirect.com/topics/chemistry/lithium-carbonate

https://www.researchgate.net/profile/Argyrios-Karatrantos/publication/344235920_Diffusion_of_ions_and_solvent_in_propylene_carbonate_solutions_for_lithium-ion_battery_applications/links/60d78785458515d6fbe0133c/Diffusion-of-ions-and-solvent-in-propylene-carbonate-solutions-for-lithium-ion-battery-applications.pdf

https://www.researchgate.net/profile/Wenfang-Gao/publication/312290768_Lithium_Carbonate_Recovery_from_Cathode_Scrap_of_Spent_Lithium-Ion_Battery_A_Closed-Loop_Process/links/5a5eaedcaca272d4a3dfcb42/Lithium-Carbonate-Recovery-from-Cathode-Scrap-of-Spent-Lithium-Ion-Battery-A-Closed-Loop-Process.pdf

https://www.sciencedirect.com/science/article/pii/S0921344921003712