31 December 2025

CleanTech Lithium PLC ("CleanTech Lithium" or the "Company")

End-of-Year Message from CEO

CleanTech Lithium PLC ("CleanTech Lithium" or "CleanTech" or the "Company") (AIM: CTL, Frankfurt:T2N), an exploration and development company advancing sustainable lithium projects in Chile has published an end-of-year message from CEO, Ignacio Mehech. The letter can be found below in full and on the Company's website here: https://ctlithium.com/investors/circulars-documents/

End-of-Year Message from Ignacio Mehech, CEO, CleanTech Lithium Plc

Dear CleanTech Lithium Community,

As 2026 approaches, I'm pleased to share my first end-of-year message as CEO of CleanTech Lithium. Having joined the company in April of this year, I have had the privilege of witnessing first-hand the hard work, passion, and ambition that defines our teams in Chile and the UK. My intention with this message is to capture some of the key operational and technical highlights and milestones we have achieved recently and the priorities for the early part of what promises to be a pivotal 2026.

Despite the challenging market conditions that we are all aware of, I'm proud to say that CleanTech Lithium has continued to develop its lithium projects in Chile, strengthen partnerships with leading companies around the world and nurtured our relationships with a wide range of stakeholders, from indigenous communities to shareholders.

Our Special Lithium Operating Contract (CEOL) Application

The Chilean government announced recently that the streamlined process has opened for new applications for Laguna Verde salar. Companies have until the end of January 2026 to apply but we will be submitting ours in the very near future.

We are confident that our application will meet all of the criteria set out by the Government earlier in the year and as part of Chile's National Lithium Strategy. If successful, there will be a negotiating period with the Government and then the award of the CEOL is expected in Q2 2026. The Ministry of Mining has already agreed on a number of CEOLs for new lithium projects in Chile, so we can expect this process for Laguna Verde's CEOL to be expeditious. There will be more detail on this in January.

Image 1: Current CleanTech Lithium's Preferential Licence Extent at Laguna Verde

Strengthening Our Value Proposition and Expanding Our Resources

2025 has also seen an updated resource estimate at our flagship project, Laguna Verde. We now have a total of 1.9 million tonnes of lithium carbonate equivalent (LCE), 0.84 million tonnes of LCE of which is in the Measured + Indicated category at a grade of 178 mg/L lithium. The new data provides increased confidence in the scale and quality of the asset and reinforces our strategy to be the next lithium producer from Chile and to advance efficient extraction technologies.

This upgraded resource will feed our Pre-Feasibility Study (PFS), which is scheduled to be published soon, once we have been accepted into the streamlined process for the CEOL. 

Producing High-grade Lithium Carbonate

This year we advanced one of the company's most strategic pillars: the development and evaluation of next-generation extraction and processing technologies. We have continued our test-work on lithium processing technologies that aim to deliver higher efficiency, improved sustainability, and stronger economic outcomes.

In January, we announced the production of high-grade lithium carbonate from our pilot plant in Copiapó. A test run volume of concentrated eluate was processed in December 2024, into an 8kg sample of high-grade lithium carbonate which a laboratory at the University of Calgary confirmed achieved 99.78% purity. With the results published in January, this exceeds the 99.6% purity standard (Chinese GB/T 23853-2022 (Type 1)) for battery grade lithium carbonate from brine. We are looking to continue this process work in the new year and scale sample production for potential strategic partners to examine, as well as proving the end-to-end the process and flowsheet contained in our PFS.

Image 2: Filter press used in the conversion process to produce lithium carbonate

A further highlight has been the collaboration with DuPont Water Solutions' newly developed nanofiltration (NF) membrane technology, which shows promise for achieving high lithium recovery while reducing environmental footprint. The test work so far has exceeded expectations in the removal of impurities and an increase in lithium recovery. We published initial results in July and will continue this test work in the new year as it has the potential to reduce both Capex and Opex costs.

These advances, as well as others still in the evaluation phase, underscore our commitment not only to produce lithium, but to producing it responsibly and efficiently. We aim to be a company that leverages innovation to minimise our impact such as water use, energy use, and operational footprint, whilst maximising returns.

Building the Future of CleanTech Lithium

Beyond operational progress, engaging with investors has been a key focus since I joined the company, and this is something I will do more of in the new year. In September, I visited London to meet shareholders, potential strategic partners, and analysts who remain deeply engaged with the global lithium narrative and CleanTech Lithium's position within it. Their feedback, enthusiasm, and long-term thinking have been instrumental as we refine our pathway to production. I plan to visit London again in the new year and look forward to continuing the informative discussions with our stakeholders and advisors during this visit.

Image 3: Ignacio Mehech joined Maximo Pacheco (Codelco), Juan Pablo Schaeffer (Anglo American), and Darryn Quayle (Worley), at the Anglo Chilean Society Event during London Metal Exchange Week, October 2025.

Our strategy for 2026 is clear: advance our projects toward final investment decisions, increase the understanding of our resource base, deepen our partnerships, and maintain our leadership in sustainable lithium development in Chile by securing the CEOL and publishing the PFS for our Laguna Verde Project. With a strengthened resource base, new technologies under evaluation, and continued support from international investors and locally with indigenous communities and the Chilean government, we are entering the new year with momentum and confidence. This will allow us to have more meaningful discussions with potential strategic partners who have the experience and financial firepower to assist us in unlocking the real potential of Laguna Verde. We are already taking actions in this regard and will provide further updates to the market soon.

To our shareholders: thank you for your trust and engagement throughout the year.

To the CleanTech Lithium team and our partners: thank you for your dedication, resilience, and belief in our shared vision. The achievements of 2025 reflect your hard work.

I wish you and your families a successful New Year. I look forward to continuing this exciting journey together and sharing many more milestones in 2026 amid encouraging signs with the lithium price and global adoption of electric vehicles and energy storage systems.

Warm regards,

Ignacio Mehech
Chief Executive Officer
CleanTech Lithium Plc

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About CleanTech Lithium

CleanTech Lithium (AIM:CTL, Frankfurt:T2N) is an exploration and development company advancing lithium projects in Chile for the clean energy transition. CleanTech Lithium has two key lithium projects in Chile, Laguna Verde and Viento Andino, and exploration stage project in Arenas Blancas (Salar de Atacama), located in the lithium triangle, a leading centre for battery grade lithium production.

CleanTech Lithium is committed to utilising Direct Lithium Extraction ("DLE") with reinjection of spent brine resulting in no aquifer depletion. Direct Lithium Extraction is a transformative technology which removes lithium from brine with higher recoveries, short development lead times and no extensive evaporation pond construction. For more information, please visit: www.ctlithium.com

**ENDS**