ProLogium and Elysian sign MoU to test 320-420 Wh/kg packs

ProLogium and Elysian Aircraft BV signed a Memorandum of Understanding to explore next-generation battery applications for large battery-electric aircraft.

Rhea-AI Filing Summary

ProLogium and Elysian Aircraft BV signed a Memorandum of Understanding to explore next-generation battery applications for large battery-electric aircraft. The MoU frames joint assessments of standard and customized technical validation, targeting pack-level energy densities of 320-420 Wh/kg to support aircraft ranges of 750-1,000 km.

The collaboration will evaluate cell-to-pack integration, weight efficiency, safety, certification constraints, and European supply-chain localization opportunities. The companies will conduct feasibility and validation work as they discuss a potential cooperation agreement; timing and commercial terms are not disclosed.

Insights

Aerospace Battery Engineer

MoU focuses on technical validation for aircraft-grade battery packs at 320-420 Wh/kg.

The memorandum outlines two validation paths: assessing existing next-generation platforms for compatibility and developing customized battery designs to meet aviation performance and safety targets. Key technical constraints mentioned include pack-level energy density, weight management, and certification standards.

Outcomes will depend on engineering validation and certification progress; subsequent filings may specify prototypes, test milestones, or qualified pack results.

Supply Chain & Sustainability Analyst

European localization and LCA considerations are explicit collaboration topics.

The MoU includes assessing local European supply and manufacturing capabilities to reduce cross-regional transport distances and lower life-cycle carbon footprint. This emphasizes supply-chain resilience and regional production as part of feasibility work.

Any manufacturing plans, timelines, or commercial commitments are not provided in the excerpt; future filings may disclose concrete site or capacity decisions.

Key Figures

Pack-level energy density target: 320-420 Wh/kg Target aircraft range: 750-1,000 km Global patents: 1,100 patents +3 more

6 metrics

Pack-level energy density target 320-420 Wh/kg aviation battery packs

Target aircraft range 750-1,000 km large battery-electric aircraft

Global patents 1,100 patents granted and pending

Cells shipped to date 800,000 cells cumulative shipments

Gigafactory ramp timeline Ramp-up Q4 2028–Q1 2029 Dunkirk facility; mass production Q2 2029

Minimum Cash condition $250 million condition referenced in forward-looking risk factors

Key Terms

Memorandum of Understanding (MoU), Wh/kg, Life Cycle Assessment (LCA), superfluidized all-inorganic solid-state battery

4 terms

Memorandum of Understanding (MoU) regulatory

"Under the MoU, the two parties will engage in discussions and assessments"

A memorandum of understanding (MOU) is a written outline where two or more parties describe their shared intentions, key terms and roles for a proposed deal without forming a full binding contract. For investors it acts like a concrete handshake: it signals the seriousness and likely direction of partnerships, mergers or supply arrangements, helping assess the probability, timing and potential impact of future agreements on a company’s value.

Wh/kg technical

"pack-level energy densities in the range of 320-420 Wh/kg"

Life Cycle Assessment (LCA) sustainability

"further reduce the overall carbon footprint from a Life Cycle Assessment (LCA) perspective"

Life cycle assessment (LCA) is a systematic analysis of the environmental impacts of a product, service or activity from raw material extraction through production, use and disposal — like tracing its ecological footprint from cradle to grave. For investors, LCA highlights hidden risks and opportunities tied to resource use, emissions and waste, helping forecast potential costs, regulatory exposure and shifting consumer preferences that can affect long-term value.

superfluidized all-inorganic solid-state battery technical

"world’s first superfluidized all-inorganic solid-state lithium ceramic battery"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did ProLogium and Elysian (TDAC) agree to in the MoU?

They agreed to explore joint development and integration of next-generation battery cells into aircraft battery modules and packs. The MoU outlines technical validation paths and supply-chain assessments aimed at aviation applications.

What energy density targets are mentioned for aviation battery packs?

The MoU mentions pack-level energy densities in the range of 320-420 Wh/kg. This range is cited as supporting large battery-electric aircraft performance objectives and target ranges.

What aircraft range do the companies reference for battery requirements?

The document references ranges of 750-1,000 km as the performance target for large battery-electric aircraft that the battery technologies would support.

Does the MoU commit to manufacturing or production timelines?

No binding manufacturing timelines are provided. The text describes feasibility assessments and supply-chain localization evaluations; commercial terms and schedules are not disclosed in the excerpt.

What safety and certification issues does the MoU acknowledge?

The MoU highlights aviation's stringent demands on battery safety, reliability, weight management, and certification, noting that technologies must undergo careful validation and long-term development before deployment.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 06/22/2026 - 06:04 AM EDT Learn about SEC filing dates

Filed by Prologium Holding Inc.

Pursuant to Rule 425

under the Securities Act of 1933, as amended

and deemed filed pursuant to Rule 14a-12

under the Securities Exchange Act of 1934, as amended

Subject Company: Translational Development Acquisition Corp.

Commission File No.: 001-42451

Date: June 22, 2026

ProLogium and Elysian Aircraft BV Sign MoU: Exploring Next generation Battery Applications in Aerospace to Advance the Vision of Zero-Emission Aviation and Future Mobility

Taoyuan, Taiwan/ Paris, France — June 18, 2026 — ProLogium, a global leader in next generation battery technology, today announced the signing of a Memorandum of Understanding (MoU) with Elysian Aircraft BV (“Elysian”), a Dutch aerospace company developing large-scale battery electric aircraft and core electrification technologies for aviation. Under the MoU, the two parties will engage in discussions and assessments regarding the potential application of next generation batteries in all-electric aircraft. According to the MoU, both parties intend to explore the joint development and integration of next generation battery cells provided by ProLogium into battery modules and/or battery packs for future aircraft applications, laying the groundwork for zero-emission air travel and next-generation mobility technologies.

The collaboration discussions will focus on assessing the feasibility of next generation battery technology in aerospace applications. The initial scope includes two technical validation directions: first, standard validation, which will evaluate the potential compatibility of existing next generation battery platforms with aircraft battery systems; and second, customized battery validation, through which the two parties will further discuss battery design directions tailored to specific specifications and performance objectives required for aviation applications. As the companies explore a potential cooperation agreement, the collaboration is expected to focus on battery technologies targeting pack-level energy densities in the range of 320-420 Wh/kg, supporting the performance requirements of large battery-electric aircraft with ranges of 750-1,000 km and to assess the potential advantages of next-generation battery technology over conventional battery technologies in improving weight efficiency, extending range, and expanding mission flexibility for aviation applications.

As the global aviation industry continues to pursue reduced carbon emissions, improved energy efficiency, and sustainable transportation solutions, battery technology’s energy density, safety, weight efficiency, and system integration capabilities will become critical factors in enabling all-electric aircraft to move toward longer ranges and greater commercial viability. With its development potential in high energy density and material-structure safety, next generation battery technology has attracted significant attention in recent years across electric vehicles, aviation, industrial applications, and the broader energy transition. However, aviation applications impose highly stringent requirements on battery system safety standards, reliability, weight management, and certification, and such technologies must still undergo careful validation and long-term development. Beyond technical performance, the localization of battery supply chains is also an important direction for advancing the sustainability of electric aviation. By assessing local supply and manufacturing capabilities in Europe, there may be opportunities to shorten cross-regional transportation distances, strengthen supply chain resilience, and further reduce the overall carbon footprint from a Life Cycle Assessment (LCA) perspective. For electric aircraft aimed at zero-emission aviation, batteries are not only the core technology powering flight, but also a key element in enhancing overall sustainability. ProLogium has long been dedicated to the research, development, and manufacturing capability build-up of next generation battery technology, while continuing to advance the potential of next-generation battery technologies across various high-end application scenarios. The MoU between Elysian and ProLogium represents the ProLogium’s progress in jointly exploring future aviation mobility and energy transition solutions with European innovators beyond its existing electric vehicle battery technology roadmap.

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Vincent Yang, Founder and CEO of ProLogium, stated: “The development of next generation batteries is not only relevant to the electric vehicle industry, but also closely connected to the future of energy transition and new forms of mobility. Aviation applications place extremely high demands on battery energy density, safety, and weight efficiency, which is why careful and rigorous assessment and validation are essential. We look forward to engaging in collaboration discussions with Elysian to jointly develop the potential application of next generation batteries in all-electric aircraft, and to lay the groundwork for lower-carbon and more efficient mobility in the future.”

Commenting on the MoU, Co-CEO and CTO of Elysian Aircraft, Rob Wolleswinkel stated: “Battery technology is a key enabler for electric aviation, but aviation requires far beyond cell performance alone. As we advance our all-electric aircraft, the E9X, and the core electrification technologies, we are also working with suppliers and partners who can help shape the broader ecosystem for electric flight. Through this MoU with ProLogium, we look forward to exploring how next generation battery technology could support safe, scalable, and zero-emission aviation.’’

About Prologium Holding Inc.

Founded in 2006, Prologium Holding Inc. (“ProLogium”) is an energy innovation company dedicated to the development and manufacturing of next-generation lithium ceramic batteries, holding over 1,100 global patents (granted and pending). In 2013, ProLogium introduced the world’s first next-generation battery architecture featuring a 100% ceramic separator, becoming the first company globally to successfully commercialize solid-state batteries. In 2025, ProLogium again led the industry by introducing the world’s first superfluidized all-inorganic solid-state lithium ceramic battery, integrating the advantages of solid-state and liquid type batteries and redefining next-generation battery technology with automation-ready, scalable mass production and cost competitiveness. In 2026, ProLogium once again received the Edison Awards Gold Award for its superfluidized all-inorganic solid-state lithium ceramic battery technology. With more than 13 years of manufacturing know-how, ProLogium is also the only company globally that can publicly demonstrate a solid-state battery mass-production line—proving that solid-state batteries are not merely a laboratory technology, but a mature solution ready for scalable manufacturing. In 2024, ProLogium inaugurated its first GWh-class gigafactory in Taoyuan, Taiwan, and has shipped more than 800,000 cells to date. In May 2024, ProLogium established its first overseas R&D center in Paris-Saclay, France, providing customized technical support for the European market. The Company’s first overseas GWh-class facility in Dunkirk, France, completed its environmental assessment and building permit process by the end of 2024, with construction expected to begin in 2026. Ramp-up is expected to begin between Q4 2028 and Q1 2029, followed by formal mass production and deliveries in Q2 2029. For more information, visit https://prologium.com/news/.

About Translational Development Acquisition Corp.

Translational Development Acquisition Corp. (“TDAC”) is a blank check company incorporated for the purpose of effecting a merger, amalgamation, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses. TDAC may pursue an acquisition opportunity in any business, industry, sector, or geographical location, and intends to focus on industries that complement its management team’s background and intends to capitalize on the ability of its management team to identify and acquire a business. TDAC’s management team is led by Michael B. Hoffman, its chief executive officer and chairman of the board of directors, and Avanindra C. Das, chief financial officer. In addition, TDAC’s board includes E. Premkumar Reddy, Curtis T. Keith, Matthew A. Kestenbaum and Christopher Jarratt.

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Forward-Looking Statements

This communication contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Exchange Act of 1934, as amended that are based on beliefs and assumptions and on information currently available to ProLogium and TDAC. In some cases, you can identify forward-looking statements by the following words: “may,” “will,” “could,” “would,” “should,” “expect,” “intend,” “plan,” “anticipate,” “believe,” “estimate,” “predict,” “project,” “potential,” “continue,” “ongoing,” “target,” “seek” or the negative or plural of these words, or other similar expressions that are predictions or indicate future events or prospects, although not all forward-looking statements contain these words. Any statements that refer to expectations, projections or other characterizations of future events or circumstances, including projections of market opportunity, number of customers and market share, the capability of ProLogium’s technology, ProLogium’s business plans including its plans to expand globally, the sources and uses of proceeds from the business combination, the anticipated enterprise value of the combined company following the consummation of the business combination, any benefits of ProLogium’s partnerships, strategies or plans as they relate to the business combination, anticipated benefits of the business combination and expectations related to the terms and timing of the business combination are also forward-looking statements. These statements involve risks, uncertainties and other factors that may cause actual results, levels of activity, performance or achievements to be materially different from those expressed or implied by these forward-looking statements. These statements are based on ProLogium’s and TDAC’s reasonable expectations and beliefs concerning future events and involve risks and uncertainties that may cause actual results to differ materially from current expectations. These factors are difficult to predict accurately and may be beyond ProLogium’s and TDAC’s control. Forward-looking statements in this communication or elsewhere speak only as of the date made. New uncertainties and risks arise from time to time, and it is impossible for ProLogium or TDAC to predict these events or how they may affect ProLogium or TDAC. In addition, there will be risks and uncertainties described in the proxy statement / prospectus relating to the business combination, which is expected to be filed by ProLogium with the SEC and other documents filed by ProLogium or TDAC from time to time with the SEC. These filings may identify and address other important risks and uncertainties that could cause actual events and results to differ materially from those contained in the forward-looking statements. Neither ProLogium nor TDAC can assure you that the forward-looking statements in this communication will prove to be accurate. These forward-looking statements are subject to a number of risks and uncertainties, including, among others, the occurrence of any event, change or other circumstance that could delay, impede or prevent the business combination or give rise to the termination of the Business Combination Agreement; the outcome of any legal proceedings that may be instituted against ProLogium or TDAC, the combined company or others following the announcement of the business combination; the inability to complete the business combination due to the failure to obtain approval of the shareholders of ProLogium or TDAC or to satisfy other conditions to closing (including the $250 million Minimum Cash condition); the amount of redemption requests made by TDAC’s public shareholders; the ability to maintain the stock exchange listing standards following the consummation of the business combination; the risk that the business combination disrupts current plans and operations of ProLogium or TDAC as a result of the announcement and consummation of the business combination; the ability to execute on its business strategy and the ability to develop and commercialize its solid-state battery technology; the ability to accurately estimate the future supply and demand for its batteries; the ability to respond rapidly to emerging technology trends; the ability to compete effectively and the ability to manage growth; the ability to recognize the anticipated benefits of the business combination; costs related to the business combination; changes in applicable laws or regulations; international trade disputes, including threatened or implemented tariffs by the U.S. and threatened or implemented tariffs by foreign countries in retaliation; the ability of ProLogium to execute its business model, including market acceptance of its planned products and services; the combined company’s ability to raise capital; future financial performance of the combined company following the business combination; the possibility that TDAC or the combined company may be adversely affected by other economic, business and/or competitive factors; risks associated with ProLogium’s efforts to commercialize its products; ProLogium’s ability to maintain its existing agreements with third parties and to negotiate and enter into new definitive agreements on favorable terms, if at all; the impact of competing products on ProLogium’s business; intellectual property-related claims against ProLogium or the combined company; ProLogium’s dependence upon its key personnel and ability to attract and retain such personnel and additional qualified personnel; ProLogium’s ability to source raw materials for its products; and other risks and uncertainties to be set forth in the section entitled “Risk Factors” in the registration statement on Form F-4 to be filed by ProLogium with the SEC and those included under the heading “Risk Factors” in TDAC’s filings with the SEC. There may be additional risks that neither ProLogium nor TDAC presently knows or that ProLogium and TDAC currently believe are immaterial that could also cause actual results to differ from those contained in the forward-looking statements.

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In light of the significant uncertainties in these forward-looking statements, you should not regard these statements as a representation or warranty by ProLogium, TDAC, their respective directors, officers or employees or any other person that ProLogium or TDAC will achieve their objectives and plans in any specified time frame, or at all. The forward-looking statements in this communication represent the views of ProLogium and TDAC as of the date of this communication. Subsequent events and developments may cause those views to change. Except as required by applicable law, neither ProLogium nor TDAC has any duty to, and does not intend to, update or revise the forward-looking statements in this communication after the date of this communication. You should, therefore, not rely on these forward-looking statements as representing the views of ProLogium or TDAC as of any date subsequent to the date of this communication.

Additional Information and Where to Find It

In connection with the business combination, ProLogium is expected to file with the SEC a registration statement on Form F-4, which will include a proxy statement of TDAC and a prospectus of ProLogium. TDAC shareholders and other interested persons are encouraged to read, when available, the preliminary proxy statement/prospectus included in the registration statement and any other documents filed with the SEC because these documents will contain important information about ProLogium, TDAC and the business combination. After the registration statement is declared effective, the definitive proxy statement/prospectus to be included in the registration statement will be mailed to shareholders of TDAC as of a record date to be established for voting on the business combination. Before making any voting or investment decision, investors and shareholders of TDAC are urged to carefully read the entire registration statement and proxy statement/prospectus, when they become available, and any other relevant documents filed with the SEC, as well as any amendments or supplements to these documents, because they will contain important information about the business combination. The documents filed by TDAC and ProLogium with the SEC may be obtained free of charge at the SEC’s website at www.sec.gov.

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Participants in the Solicitation

ProLogium, TDAC and their respective directors and executive officers may be deemed to be participants in the solicitation of proxies from TDAC shareholders with respect to the business combination. A list of the names of TDAC’s directors and executive officers and information regarding their interests in the business combination will be included in the proxy statement/prospectus for the business combination when available. Additional information regarding the persons who may, under the rules of the SEC, be deemed participants in the solicitation of TDAC shareholders in connection with the business combination, including a description of their direct or indirect interests, by security holdings or otherwise, will be set forth in the proxy statement/prospectus for the business combination when available.

No Offer or Solicitation

This communication is not a proxy statement or solicitation of a proxy, consent or authorization with respect to any securities or in respect of the business combination and does not constitute an offer to sell or the solicitation of an offer to buy any securities of ProLogium or TDAC, nor shall there be any sale of any such securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of such jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of the Securities Act, or an exemption therefrom.

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