Grease 

TLT Sounding Board January 2024




Executive Summary
Lithium-based greases have been widely used due to their high temperature performance, water resistance and shear stability. However, limitations such as availability and environmental concerns are increasing the demand for alternatives. The use of lithium in electric vehicle (EV) batteries is a leading factor in the evolving lithium outlook, and alternatives for EV applications also are under consideration.
 
Q.1. What are probable thickener chemistries that can be an alternative to lithium-based greases?
Calcium sulphonate polyurea.

Calcium sulfonate and aluminum complex.

Calcium-based.

Calcium anhydrous.

Calcium sulphonate.

Aluminum complex calcium sulfonate.

The best is calcium sulfonated complex by far.

Calcium sulfonate, aluminum complex.

We have brilliant engineers working on that very issue. They will adapt related chemistry to build a work around. Sometimes old technology is the best technology.

Organoclay.

Calcium sulfonate, calcium complex, polyurea, aluminum complex and anhydrous calcium greases for some applications.

Calcium anhydride, calcium sulfonate complex, barium complex, polyurea.

A lot of excellent work is being done on utilizing calcium sulfonates. Also calcium/lithium grease to stretch the lithium supply.

Polyurea, calcium sulfonate complex and, in some cases, bentonite.

Calcium would be the more obvious choice due to its capabilities around water and its close compatibility with lithium-based grease.

Aluminum complex and, of course, I am a big fan of calcium sulphonate.

Anhydrous calcium is functionally similar to simple lithium thickeners, and since they are compatible, they are the most likely candidate for replacement. For lithium complex grease alternatives, higher temperature capable greases such as calcium sulfonate and polyurea would be the most likely alternatives.

Do you think polyurea greases are better than lithium greases in terms of oxidation stability?
Yes 77%
No 23%
Based on an informal poll sent to 15,000 TLT readers.

Hydrodynamic way.

Calcium sulfonate.

Thickener chemistries are application driven. Almost any grease thickener may be used as a replacement for lithium soap thickener. Calcium sulfonate for heavy industry or polyurea for light industry or automotive. There are other soap thickeners that can be used instead of lithium: calcium, barium or aluminum soaps. Clay and other solids can be used as thickeners. 

Polymers like polytetrafluoroethylene (PTFE) would be an expensive replacement.

Overbased sulfonate.

The easiest conversion of simple lithium greases would be to anhydrous calcium greases. Anhydrous calcium has a lower dropping point compared to simple lithium, which might be a hurdle. People still think that dropping point is a performance parameter, which it is not but rather a test aimed for production control. There are already available anhydrous calcium greases that could replace your typical lithium EP 2. Replacing lithium complex greases will be a bit more challenging. There is no “one solution” for this. Depending on application and performance requirements, calcium sulfonate complexes or polyureas could be good alternatives.

Aluminum complexes also might get a revival if cost is the driving factor.

Polyurea, calcium sulfonate complex, calcium greases.

Calcium complex. Polyurea. PTFE.

Calcium sulfonate and polyurea are the most promising alternatives to lithium complex in many grease applications. Polyurea has some manufacturing limitations due to the toxicity of the starting materials, especially the isocyanates. Some current grease plants are not suited for the manufacture of polyurea greases.

Calcium sulfonate complex.

Polyurea, calcium-based thickeners.

Polyurea, sodium-based or possibly polymer structures.

Calcium sulfonate and polyurea-based thickeners from a performance standard point. Compatibility with existing lithium grease can limit their ability as a replacement unless test for compatibility and develop a changeover plan.

Polyurea, calcium sulfonate and aluminum complex in place of lithium complex. Anhydrous calcium in place of simple lithium.

Given the cost to performance benefit and for most general applications, calcium sulfonate complex greases will likely emerge as the dominant thickener type, especially given the amount of work from the specialty houses in developing calcium sulfonate complex formulations that performance offsets. This said, calcium sulfonate complex thickener content has a drawback in that it will struggle to meet the noise requirements in electric motors for everything from small device to full EV applications.

Calcium sulfonate for their outstanding dropping point, natural extreme pressure (EP) and excellent water washout resistance.

Polyurea is superior for most automotive grease applications, whether EV or ICE.

Calcium, aluminum, polyurea.

Why not to stop thinking about lithium metallic-based grease rather to think and educate others to go for polyurea-based grease where so many advantages are there in terms of reliability, environmental sustainability and energy saving. This is my view based on my limited knowledge about the beauty of lubricant tribology.

Polyurea thickener may be chosen.

Calcium complex, calcium sulfonate, polyurea and aluminum complex.

Polyurea thickener.

Calcium sulfonate, clay, several aluminum compounds.

Thickener polyurea.

Polymer thickeners.

Overbased calcium sulfonate.

Calcium-based new generation.

Aluminum complex. Calcium sulfonate.

Anhydrous calcium greases are the natural alternative for simple lithiums. For complex lithium soap it depends on the operating conditions. Possible alternatives can be polyurea (e.g., e-motors), calcium sulfonate complexes (heavy applications) and aluminum complex.

Calcium complex and polyurea.

Depending on application, calcium soap thickeners can be a good option. If higher temperatures are needed, then it’s useful to explore polyurea thickeners.

Calcium sulfonate, calcium complex.

Q.2 What are your views on the lithium use in EV batteries and its implications for the grease industry?

Waste of a vital resource. EV use has taken away a versatile grease thickener for many grease-lubricated applications.

Use of lithium in EV batteries will increase resulting in higher prices.

Price levels due to supply and demand may be the first indicator that a shift away from lithium is required for grease. How this will develop is unclear, but there is a need to specify and produce alternative formulations.

It will definitely affect the grease market and is already. The pricing of lithium has skyrocketed causing lithium and lithium complex greases to be priced now in the same category as calcium sulfonate complex greases, which were always higher based on soap to oil content.

Energy-in-energy-out protocol determines that the use of lithium in EV batteries is a very poor use of this valuable resource.

It was used in this application first. Users of grease will have to choose more costly alternatives, which can many times last longer in service. So, it will not affect the grease industry overall except that different thickeners will fill the gap.

Increase in the prices of lithium hydroxide and maybe shortage.

It will drive the cost of lithium up and make finding alternative grease thickeners a must.

Lithium batteries are currently the best available for now, but overall it is not feasible to consider it as the best material for batteries. They are not stable, have a relatively low life and are so very expensive to replace when they do fail.

The lithium use in batteries will drive the cost of lithium-based greases past the pain point for most users, requiring the introduction of some other material for grease thickening.

In the near term, EV batteries have caused a demand spike that has affected global lithium pricing. As a result, lithium-based greases have become more expensive than other types of grease. The alternatives are likely to gain a foothold as the overall pricing/performance ratio is better. Lithium-based greases will be reduced in use, but not entirely due to the OEM use and recommendation.

Complex lithium greases will continue to be used in EV and the whole grease industry in the near future.

It depends on batteries generation, but we could use the same lithium used in the grease technology.

Although lithium-based grease has been a staple of the lubrication industry for a considerably long time due to its relatively low cost, good mechanical stability and water resistance, it is by no means the only thickener available, and it could be argued that its success and low cost are in part due to the vast quantities produced, and the economics of lower cost production that goes along with such volume. However, with the competing demands for lithium from the battery industry, both vehicle and otherwise (such as solar energy storage), there is a need to consider other thickeners, and in my view, those mentioned previously can be used successfully across a range of applications, but require much more careful selection than has historically been the case with multipurpose lithium and lithium complex greases.

Unless other sources of lithium are developed, lithium’s use in greases will decline quickly.

Prices of lithium will probably stabilize when new batteries technologies will arise.

Other suitable thickeners are available.

There is still plenty of lithium in the world, but it is becoming more difficult to extract; thus the cost is increasing. More technology development is needed to access the more difficult lithium sources.

It would be very likely that the demand for lithium will continue to increase ahead of the supply (and driving up prices). The increased cost of lithium greases will drive the demand toward alternative thickeners.

They will be applied with a decreasing but stabilized tendency. Calcium-based and polyurea-based greases can be a developing alternative.

I think it will be a major impact in a couple years.

Lithium is getting expensive.

It may reduce the available resources and cause price increases.

Based on my experience, I haven’t encountered any major concerns regarding lithium availability. Many of the issues that surface can generally be attributed to one of two factors. First, some instances involve people misrepresenting a price increase as a supply problem. Second, some companies are utilizing the lithium supply situation as a means to promote their non-lithium technology, aiming to boost their sales. It’s noteworthy that new lithium plants are consistently coming into operation, with emerging suppliers entering the market. Additionally, the vast majority of suppliers are keen on broadening their customer base, which discourages them from neglecting the grease industry. Furthermore, I’ve been in contact with newly formed companies interested in supplying lithium to the grease industry.

Can polyurea grease replace lithium greases in automotive lubrication?
Yes 70%
No 30%
Based on an informal poll sent to 15,000 TLT readers.

Certainly puts pressure on supply and availability for grease, but alternative metals for EV batteries will shortly be available as well as for grease thickener, so demand will stabilize.

We have already had to source alternative greases due to a short supply of lithium-based grease.

No challenges or concerns on supply shortages. In time, battery technology will surpass lithium as a base metal for battery manufacturing.

It will hurt the grease industry.

Lithium supply is tightening in the market, and cost has increased substantially over the last few years.

This may cause cost increases because market demands may restrict access to lithium.

As the cost increases, alternatives will be found.

Very bad. EV might be too hyped.

Lithium-based grease might survive if EV is replaced by other engines such as ammonia-powered engines.

The use of lithium-ion batteries is going to cause the price of lithium greases to increase, possibly to the point where they can become too expensive to use.

The prices of lithium greases will increase, which will draw attention to the possibility of using better greases thickened by polyurethanes and calcium sulfonates.

Demand from EVs will lead to scarcity of lithium and prohibitive costs for grease formulators.

It presents the challenge of unbalance between supply and demand. This leads to supply insecurity and elevated costs. The purchasing power of the grease industry also is in decline for this material, and the industry cannot expect the historical priority from lithium suppliers.

Solid battery will take a huge place in the coming years, and some of them are based on lithium.

It will continue to drive up the price of raw materials. However, it may result in superior greases when R&D to develop new thickeners proves fruitful.

It is good that we force people to think and that they hesitate before selecting a lithium grease out of habit. For many grease lubricated systems, there are alternative greases that are equally good, and in many cases outperform lithium.

It’s a serious worry, and alternative thickeners need to be introduced.

Batteries at present require lithium in such quantities as to hinder lithium grease production. It will only get worse.

As demand for EVs increases, the lubricant industry will need to explore alternatives.

The supply will be disrupted, and the price may not be favorable for grease making. This is the right time to seek alternatives to lithium for grease manufacturing.

Will cause supply problems and reach problems in the industry.

Wouldn’t polyurea be a better grease for EVs?
 
Editor’s Note: Sounding Board is based on an informal poll sent to 15,000 TLT readers. Views expressed are those of the respondents and do not reflect the opinions of the Society of Tribologists and Lubrication Engineers. STLE does not vouch for the technical accuracy of opinions expressed in Sounding Board, nor does inclusion of a comment represent an endorsement of the technology by STLE.