Company

Joe Mastrangelo is driven by a vision of energy abundance as the foundation of human progress.

Joe joined Eos Energy Enterprises as Chief Executive Officer in 2019, bringing three decades of leadership across the global energy sector. His career spans technology innovation, industrial manufacturing at scale, and worldwide commercial deployment—providing the rare, end-to-end perspective required to steer energy systems from laboratory breakthroughs into real-world impact.

Throughout his career, Joe has worked to build cultures that nurture the unconventional thinkers and committed doers needed to tackle problems others consider impossible. Whether integrating complex organizations or building teams from the ground up, Joe recognizes that people are the key to success and strives to create environments where bold ideas are matched by disciplined execution.

Before joining Eos, Joe served as CEO of GE’s Power Conversion business and as President and CEO of Gas Power Systems for GE Power, leading global operations of more than 15,000 employees across 60+ countries. These roles reinforced a conviction central to his vision: revitalizing America’s ability to design and manufacture physical, industrial-scale technologies is critical—not only to economic competitiveness, but to addressing the world’s greatest challenges.

At Eos, Joe is translating that conviction into action. The company is rebuilding U.S. manufacturing capacity to produce breakthrough zinc-based, high-density battery energy storage at gigawatt scale—creating American jobs while delivering technology the world urgently needs. He also serves on the Pittsburgh AI Strike Team 2.0 Board, helping connect advanced manufacturing with artificial intelligence to accelerate innovation and reclaim the region’s historic industrial leadership.

Bringing over 25 years of finance, customer, and energy industry experience to the organization, Nathan Kroeker transitioned to CCO of Eos in March of 2025, after serving as CFO from January of 2023. In his time as CFO, Nathan secured over $850 million in transformative financing, positioning Eos for significant operational expansion. Having held financial leadership roles with several energy firms during his career, Nathan has a keen awareness of how the energy sector has evolved over the last decade, and he understands the challenges that lie ahead. Prior to joining Eos, Nathan served as Chief Financial Officer of Spark Energy before taking over as Chief Executive Officer in 2014 when he led the company’s IPO—the first independent retail energy company to successfully IPO on the NASDAQ. His prior experience as CEO gives him a unique understanding of both the complexities of the industry and the evolving needs of customers, while his time as CFO offered a distinct perspective of the financial and commercial landscapes of the industry, allowing him, in his new role as CCO, to create customer-centric solutions that are not only impactful, but also financially sustainable.

Nathan earned his undergraduate degree in Accounting from the University of Manitoba where he graduated with distinction. He believes in the fundamental role of energy storage in the global energy transition, and his business acumen is a key asset in maintaining Eos’ leadership momentum as we shift into a new era of electrification.

As Chief Operating Officer, John will lead the company’s operations, supply chain, and manufacturing strategy. John has more than three decades of experience in global manufacturing, operations, supply chain and business development from his tenure at Jabil Inc., a multibillion-dollar global manufacturing solutions provider. Most recently, John served as Senior Vice President of Operations for Europe and the Americas, generating more than $14 billion in annual revenue and overseeing over 70,000 employees across 30+ factories worldwide.

Recognized for his transformative leadership, John has led multiple manufacturing facilities to win the prestigious Shingo Prize for Operational Excellence. His strategic planning, disciplined execution, and ability to scale complex operations have consistently driven meaningful growth and operational efficiency.

After starting as a Senior Battery Scientist at Eos in 2015, Francis Richey held positions as product development manager and was named Vice President of R&D in December 2020. His vast knowledge of electrochemical engineering and passion for scaling technology from the lab to a commercial product has been integral for advancing and refining Eos Znyth™ battery technology and keeping the organization at the forefront of developing battery storage alternatives to lithium-ion. After graduating with a Bachelor of Science in Chemical Engineering from Penn State University and a Ph.D. degree from Drexel University with a focus on Chemical and Electrochemical Engineering, Francis began his career as a Postdoctoral Research Scientist at Stanford University leading a collaborative research effort between UC Berkeley and Stanford to investigate corrosion mechanisms in aqueous Metal air batteries. He holds 9 patents, has publications in the Journal of the Electrochemical Society and Journal of American Chemical Society, and has presented at numerous electrochemical conferences on fuel cells, batteries, and capacitors. By advancing zinc-based battery technology and leading R&D efforts at Eos, Francis is a driving force for helping Eos change the way the world stores power.

Michael brings over 25 years of experience across a breadth of legal functions. He served from 2020 to 2023 as General Counsel, Chief Compliance Officer, and Corporate Secretary at Trecora Resources, a NYSE-listed international diversified technology and specialty materials company based in Sugar Land, Texas. As Trecora’s General Counsel, he oversaw all legal and compliance matters worldwide for the company including the successful sale of the company to a private equity firm in 2022.

Before Trecora, from 2016 to 2020, he was the Vice President and Deputy General Counsel, & Assistant Secretary at Celanese Corporation, a Fortune 500 international diversified technology and specialty materials company based in Dallas, Texas. In that role, he served as the lead lawyer overseeing the legal affairs for both the global $4 Billion Acetyl Chain business and the global Supply Chain organization. Prior to that role, he held several positions from 2004 to 2016 at FMC Corporation, a Fortune 1000 international diversified technology and specialty materials company based in Philadelphia, Pennsylvania. While at FMC, he served as Assistant General Counsel and Assistant Secretary during which he was the company’s chief M&A and corporate counsel, and prior to that, served as division general counsel for FMC’s global Health and Nutrition division. Before FMC, he worked for the law firms of Morgan, Lewis, Bockius LLP in Philadelphia from 2000 to 2004, and Blank Rome LLP in Philadelphia from 1996 to 2000, and as a Law Clerk and Court Mediator for the New Jersey Superior Court in Camden, New Jersey from 1995 to 1996.

Michael graduated with a Juris Doctor degree from Emory University School of Law, and a Bachelor of Arts degree with distinction from the University of Pennsylvania. Outside of work, Michael serves as a current member and former Chairman of the Board of Directors for the North Texas Chapter of the American Red Cross.

Michelle Buczkowski is driven by a belief—and a career spent proving—that people power the world.

Michelle joined Eos Energy Enterprises in 2024, bringing nearly 20 years of experience in talent acquisition and development, workforce transformation, and organizational culture and communications in highly-regulated, operationally-complex industries. She is sought out for building teams with the resilience to take on rapid growth and dynamic change and deliver with excellence—in ways that benefit not just the companies Michelle works for, but every individual within them.

Throughout her career in and around Pittsburgh, one of the United States’ historic centers of industrial leadership, Michelle has led the alignment of people strategies with organizational goals, unlocking employee potential to drive corporate impact. Michelle shepherded CONSOL Energy’s employee base through the Marcellus Shale natural gas boom, architected a multi-year roadmap that brought the PNC Bank’s vision of a “Talent-Focused Culture” to life, and, most recently, as Managing Director of Human Resources at Duquesne Light, partnered closely with union leadership and executive teams to transform compensation strategies and labor relations.

At Eos, as the company’s first Chief Administration Officer, Michelle is delivering on her reputation as passionate and ambitious but clear-thinking and pragmatic leader of people. Reshaping how the company leads, engages, and evolves its workforce to unleash the ingenuity and determination of every Eos employee, Michelle is creating the organizational capacity—from the R&D lab to the factory floor—to meet the moment and the mission to build the energy storage the world urgently needs.

Pranesh started at Eos as Vice President, Engineering Control Systems on July 11, 2022. Since then, he has been leading the development of the Gen 3.3 BMS and improvements to the Gen 2.3 BMS in support of field deployments. Prior to joining Eos, he was VP of Engineering at ESI Elevator Systems. He is a proven technical leader with an extensive background in Controls focused on electrical systems. He previously served as Sr. Director, Electronics and Software for Nidec Motor Corporation and led the grid controls development for A123 Energy Solutions, a Li-ion battery manufacturer. Pranesh holds an M.S.in Electrical Engineering from Missouri University of Science and Technology, and a B.E. in Electrical Engineering from B.M.S. College of Engineering, India.

Justin joined Eos in April 2024, bringing with him a wealth of experience from his role as Managing Director of Business Development & Marketing for the Sustainable Solutions division at Duke Energy. With a strong background in technical sectors, he has successfully led and developed world-class teams in areas such as renewable energy, industrial automation, power distribution and generation, as well as service and software solutions.

Justin holds a Bachelor of Science in Mechanical Engineering and is certified as a Six Sigma Green Belt. His expertise lies in designing, building, marketing, and contracting complex technical products and solutions, with a proven track record of aligning offerings to maximize customer value. Throughout his career, Justin has demonstrated a commitment to fostering high-performing teams that drive innovation and achieve exceptional results.

Mike brings 27 years of global construction and project management experience across 49 states, 37 countries, and 6 continents, with a strong background in generation, transmission, distribution, substations, renewables, and data centers. Before joining Eos in October 2024, Mike successfully led renewable energy projects, including Battery Energy Storage Systems (BESS), expanding service areas and improving margins in the power and renewable sectors. His track record includes navigating complex global operations, ensuring safety compliance, and growing regional footprints to drive enterprise-level growth.

In his role as Senior Vice President of Projects and Service, Mike will oversee project management, and field service for the successful execution of customer projects.  He will play a critical role in coordinating with Manufacturing, Commercial, and Engineering teams to support Eos’ commercial growth focused on delivering solutions that meet the highest standards for both Eos and its customers. Mike earned his Bachelor’s degree in Business from Capella University.