Not according to research:
As I said, thinner layers for higher power, thicker layers for higher capacity.
http://jes.ecsdl.org/content/162/7/A1196.full
yes a thicker electrode will store more energy but that is only a small piece of the layer cake. you have no idea what the main drivers of cost are when you make all the components (electrolyte, cathode, anode, foil, and separator, can) yourself. here let me help you (note all these cost estimates are totally wrong and I'm not about to give you the real floor price on any of them)
note their model comes up with materials at 49% total cost of a cell. The gigafactory will be over 90% material cost and those material costs will not be based on purchasing the materials (ready made electrolyte, cathode, anode, foil, and separator, can) it will be base on purchasing raw materials and making all the components. on top of that they will not be paying spot price as they are buying direct from north american mines (long term subsidized (but don't call it that) sweetheart deals the same as China does it)
http://www.cse.anl.gov/batpac/files/BatPaC ANL-12_55.pdf
The recent penetration of lithium-ion (Li-ion) batteries into the vehicle market has prompted interest in projecting and understanding the costs of this family of chemistries being used to electrify the automotive powertrain. Additionally, research laboratories throughout the U.S. Department of Energy complex and various academic institutions are developing new materials for Li-ion batteries every day. The performance of the materials within the battery directly affects the end energy density and cost of the integrated battery pack. The development of a publically available model that can project bench-scale results to real world battery pack values would be of great use. This first version of the model, the battery performance and cost (BatPaC) model, represents the only public domain model that captures the interplay between design and cost of Li-ion batteries for transportation applications.
The amount of cobalt and nickel, as well as ease of manufacture, controls the end price for apositive electrode material. For example, the NMC-441 is less expensive than the NMC-333 asthe cobalt quantity is significantly reduced. The market prices for cobalt and nickel metals varydramatically from year to year. Reducing the quantities of these materials in the positiveelectrode will reduce the total price and price volatility. Researchers at TIAX LLC have treatedthis variation and shown the significant effect on end battery cost.10 The average traded metalprices and the 95% confidence intervals for the last 25 years is 44.4±18.3 $/kg and 14.9±7.6 $/kgfor cobalt and nickel respectively. These numbers are based on historical prices for the metals ascollected by the United States Geological Survey (USGS).48 The metal prices are indicators forhow the intercalation material cost will relate when compared to one another. The fact thesematerials are not earth abundant means they will not benefit as much as other materials fromincreased scales of production.We employ the relationship in Equation 5.1 to systematically calculate the cost of the transitionmetal based spinel and layered compounds. The final cost, C, of the lithiated oxide depends onthe baseline cost, C0, and the contributions of the lithium and transition metal raw materials, Ci.The molar stoichiometry, xi, is transformed to a mass basis with the molecular weight of the rawmaterial, MWi, and the final product, MW.
The baseline cost is the sum of the cost for processing,additional raw materials, and profit margin associated with the manufacture of the materials. Weassume a baseline cost of $7/kg for single metal containing oxides (LMO and LCO) and $16/kgfor the co-precipitated metal oxides such as NMC-333 and NMC-441. NCA is known to have aslightly lower yield and requires additional raw materials resulting in an assumed C0 = $20/kg.The costs for Li, Ni, Mn, and Co are taken to be 0.22, 0.87, 0.15, and 2.6 $/mol respectively. Thehistorical average metal prices for Ni and Co are used recognizing that these values will fluctuateover time. Aluminum is assumed to be similar in cost to manganese for these calculations. Onemay directly translate these numbers to raw materials costs resulting in $6/kg for Li2CO3,$5.6/kg for NiSO4, $16.9/kg for CoSO4, and $1/kg for MnSO4. Calculations are also shown inTable 5.1 using $4.8/mol ($81/kg) for cobalt as a demonstration of the upper 95% confidenceinterval cobalt price on the end material cost.
In general, earth abundant elements should be the dominate transition metals used if a low costpositive electrode is desired. Both iron and manganese are abundant and inexpensive transitionmetals for intercalation materials. Comparison of the iron phosphate, LFP, to manganese spinel,LMO, reveals how processing costs contribute to the end price of a material. LMO is relativelyeasy to manufacture. In contrast, LFP requires a reducing atmosphere and a carbon coating stepto reach the end product. The increased complexity in the manufacturing process is realized inthe price. However, one could argue that the manufacturing cost will decrease with increasedknowledge from larger scales of production.
5.2.1.2 Negative Electrode Active MaterialsWhile several negative electrode materials exist for Li-ion batteries, carbon materials in the formof graphite and/or hard carbon are still used in the vast majority of commercial cells. Graphite 57offers the greatest energy density while hard carbon is said to enable high rate capability withdecreased risk of lithium plating (an undesired side reaction) during high charge rates. We havechosen synthetic graphite as a generic carbon electrode in our model. Significant differences incost and performance will exist between synthetic, natural, and coated-natural graphite. Themethod of production and necessary heat-treatment will control the end cost. Manymanufacturers use a proprietary blend of natural and synthetic graphite and/or hard carbon in thenegative electrode of their cells. The user of the model may feel free to vary the price dependingon the application of interest.The lithium titanate electrode, LTO, offers an interesting option compared to graphite. Unlikegraphite, LTO operates within the stability window of the electrolyte. The higher electrodepotential, 1.5 V vs Li, dramatically reduces or eliminates the formation of the solid electrolyteinterphase (SEI). As a result, nanoparticle-based LTO may be implemented without concerns ofincreased side reactions with the electrolyte. The reduced nanoparticle dimensions increase theavailable surface area for reaction while simultaneously shortening the diffusion length. Both ofthese factors combined with the lack of SEI dramatically reduce the impedance of the electrode.5.2.1.3 Electrolyte and SeparatorThe electrolyte used in this model is based on a lithium hexafluorophosphate salt, LiPF6,dissolved in a carbonate based solvent system. The carbonate solvent system is a blend ofethylene carbonate, EC, and a linear carbonate such as ethyl methyl carbonate, EMC, or dimethylcarbonate, DMC.
Other chemical additives may be used to limit the capacity and power fade ofthe battery over time. Polymers may be added to the electrolyte as either a minor or majorcomponent. This is not discussed in any further detail in this work. The price of 18 $/kg, about22 $/L, is only for the base electrolyte (i.e. no additional additives).The separator is typically a porous membrane based on polypropylene (PP) and sometimesincludes a polyethylene (PE) middle layer. PP and PE are very inexpensive raw materials andthus the suggested cost of $2/m2is in large part due to the manufacturing process required toform the porous network in the membrane.
As competition and scale of manufacture increase,the prices of the separator may fall closer to $1/m2. However, the cost of improved technologymay offset some of this cost reduction, so we have retained our cost estimate of $2/m2. As safetyis a major concern for Li-ion batteries, the separator plays a key role in isolating the oxidant fromthe fuel. If the two charged electrodes contact each other (short), then a run-away reaction ispossible. Separators have been designed to “shut-down” or melt at key temperatures. The middlePE layer is the shut-down feature in our proposed separator. Ceramic coatings have also beenused to ensure structural integrity. Many other approaches are being developed to increase thesafety of Li-ion batteries. The user of the cost model should account for the specific separatortechnology in the price and dimensions (thickness and porosity) of the separator as needed.
5.2.1.3 Current Collector FoilsThe current collector foils are based on copper metal for the negative electrode and aluminum forthe positive electrode. However, the LTO anode material, because of its high voltage relative tolithium, enables the use of aluminum as the negative electrode current collector. The price of 58these foils is based on raw materials and manufacturing costs. The aluminum foil is produced byrolling of thicker stock foils into thinner and thinner sheets. On the other hand, copper foil ismore likely to be produced through an electrodeposition process. The foils are 12 microns and 20microns thick for the copper and aluminum current collectors respectively. The foils used inbatteries have additional requirements beyond the cheapest product available. Surface treatmentsare often necessary to promote adhesion of the composite electrode to the foil surface. Inaddition, alloying of the foil may be necessary to achieve the required material properties forlong life.The raw material contributions to the foil price will vary with the volatility of the market pricefor the metals. Figure 5.1 displays the metal ingot price contribution on a $/m2basis. Thesenumbers are based on historical prices for the metals as collected by the USGS.48 The values forboth aluminum and copper tend to vary significantly over the time period examined. The pricefor copper is more volatile and always more expensive than aluminum. Analysis of Figure 5.1reminds the user of the cost model that cost quotes are only valid for a short period. As themarket price for raw materials changes, so will the price for the finished product.Conversations with manufacturers and suppliers lead us to take a price of 1.80 and 0.80 $/m2forbattery grade copper and aluminum foil respectively. We point out that the current metal ingotprice is only a small contribution to the end foil price being about 16 % of the aluminum foilprice and 23 % of the copper foil price. Thus, a doubling of the ingot prices would onlymoderately increase the foil prices.
5.2.1.4 Additional Electrode ComponentsThe binder and conductive additive in the positive and negative electrodes add a small but realcost to the battery. The conductive additive, more common for the positive electrode, was pricedat 6.80 $/kg for a high purity and moderate surface area carbon black material. The binder,perhaps PVDF or CMC based, is assumed to be 10 $/kg. The N-Methyl-2-pyrrolidone (NMP)solvent for the PVDF binder is estimated to be 3.20 $/kg. Most of the NMP is recovered afterevaporation and recycled as discussed in section 5.3.3. Only the small amount lost in processingneed be replaced. No cost is assumed for water used in the electrode slurry processing.
