Adden Energy

Table of Contents

⚠ Disclaimer: This entry may be incomplete, out of date, or inaccurate. It is AI-maintained on a best-effort basis. Do not rely on it as a sole source — verify claims independently using the sources listed below.

Summary

Adden Energy is a Waltham, Massachusetts startup spun out of Harvard SEAS, where Associate Professor Xin Li’s group developed a lithium-metal solid-state cell with a self-healing solid separator exclusively licensed to the company. It raised a $15M Series A on 25 October 2024 led by At One Ventures to build a roll-to-roll pilot line at its Waltham headquarters and to scale cell size 100-fold. Its fast-charge and cycle-life figures come from lab-scale cells and company statements; no newer financing or customer announcement was found in the sources reviewed as of October 2026.

Key Facts

Founded: 2022 (exclusive Harvard license); HQ Waltham, MA
Type: Private startup
Stage: Series A, $15M (2024-10-25); roughly $20M total raised including a $5.15M seed (company-reported)
Investors: At One Ventures (lead), Primavera Capital Group, Rhapsody Venture Partners, MassVentures (Pulse 2.0)
Technology: lithium-metal solid-state cell with a self-healing solid-state separator licensed from Harvard
Company claims: charge in under 10 minutes in EV-compatible pouch cell prototypes; nearly 10× the lifetime of conventional batteries; goal of EV cost parity with combustion vehicles by 2028; At One partner cites a 30% cost-per-kWh reduction (investor statement)
Lab results (Harvard): over 10,000 cycles with fast charging in small cells (Harvard SEAS)
Status: pre-production; pilot line funded; a February 2025 commissioning report was not re-verified

What It Is / How It Works

Adden Energy’s technology originates from research by Associate Professor Xin Li at Harvard SEAS. The cell architecture uses a thin-film solid-state electrolyte with a lithium metal anode — the same general approach as other solid-state programs, but with particular attention to the lithium-electrolyte interface stability that typically causes degradation in competing designs.

The key performance claims are two-sided: very fast charging (under 10 minutes in company pouch-cell prototypes) and long cycle life (over 10,000 cycles in Harvard’s lab-scale cells). If both are reproduced in automotive-grade large-format pouch cells, the technology would represent a step-change in EV practicality.

The company’s October 2024 Series A is specifically earmarked for building a pilot production line at Waltham to manufacture EV-compatible pouch cells — the critical step between lab-scale coin cells and the format required for OEM validation.

Adden is still at an early stage relative to Factorial Energy or QuantumScape. The defining question is whether the lab-scale results — achieved in small coin cells under controlled conditions — can be reproduced in the larger, thicker pouch cell formats required by automotive customers, where thermal management and interface uniformity become significantly harder.

Notable Developments

2026-10: No new funding, partnership or pilot-line announcement was found; the company website (checked October 2026) lists a waitlist, a 2024 Nature Materials publication and a leadership team including CTO Luhan Ye and COO In Kim. (Adden Energy)
2025-02: Report that an R&D pilot line was commissioned at Waltham (not re-verified in this review).
2024-10: $15M Series A raised, led by At One Ventures; earmarked for pilot production line construction for EV pouch cells.
2022: Seed round of $5.15M raised; exclusive technology license secured from Harvard University Office of Technology Development. Led by Primavera Capital Group.
2022: Company founded following Harvard SEAS research publications demonstrating 10,000-cycle solid-state performance.

Key People

Xin Li — Associate Professor, Harvard SEAS; Co-Founder

LinkedIn: linkedin.com/in/xin-li-5ab9601b
Google Scholar / Harvard: scholar.harvard.edu/lixin | seas.harvard.edu/person/xin-li
Role: Lead researcher and academic co-founder; his lab originated the core cell technology
Education: (undergraduate/graduate details not confirmed from public sources; postdoc MIT 2011–2015)
Career (reverse-chronological):
- Harvard SEAS (2015–present): Associate Professor of Materials Science
- MIT (2011–2015): Postdoctoral researcher, battery materials
Notes: Li’s postdoc work at MIT focused on traditional lithium-ion nuances, leading into the solid-state research that eventually became Adden’s technology. No confirmed overlap with other documented companies’ personnel via MIT connection, though MIT’s materials science programs are a known source of battery entrepreneurs.

William Fitzhugh — Co-Founder and CEO

LinkedIn: linkedin.com/in/wfitzhugh
Role: CEO and operating co-founder; manages commercialization and pilot production
Education: University of Colorado Denver (BS Physics 2012; MS Integrated Science 2015) → Harvard University (MS Applied Physics 2017; PhD Applied Physics 2020)
Career (reverse-chronological):
- Adden Energy (Feb 2022–present): Co-Founder and CEO
- Innovation Crossroads (Jun 2019–Jun 2021): Entrepreneurial Fellow (Oak Ridge National Laboratory-affiliated entrepreneurship program)
- American Nanotechnologies, Inc. (Dec 2015–Feb 2022): Founder and CEO (ran in parallel with Harvard PhD)
- Harvard SEAS, Xin Li lab (Sep 2015–May 2020): Graduate student researcher

Titles confirmed in the October 2024 announcement: William Fitzhugh, Co-Founder and CEO; Xin Li, Harvard professor, Co-Founder and Chairman. Other details are as of the previous review.

Other leadership (company website, October 2026)

Luhan Ye, PhD — Co-founder and CTO; In Kim, PhD — COO and Board Director; Pu Zhang — CPO; Kimberly Branson — VP Business Development; Fred Hu, PhD — Co-founder and Board Director. LinkedIn: not found.

People — Last Reviewed: 2026-10-20

Supply Chain Position

Adden Energy operates at the Cell Manufacturing layer (pre-production / pilot scale), with its thin-film solid-state cells being built on a pilot line at Waltham, MA. The company is at an early stage and has not disclosed specific upstream supplier agreements. Like all solid-state programs using lithium metal anodes, it requires high-purity lithium metal foil. Downstream customers are not yet disclosed; the Series A raise is aimed at producing EV-compatible pouch cells for OEM sampling, with no OEM partner disclosed in the sources reviewed. No shared supplier flags identified at this stage.

Claim Verification

Claim: 10-minute fast charging (0–100%) at room temperature

Status: Partially verified (lab scale only; company states pouch-cell prototypes)

Supporting sources:

Harvard SEAS — Fast Charging Over 10,000 Cycles — Published academic results from Xin Li’s group; lab-scale coin cells
CleanTechnica (Jan 2024) — Describes 3-minute charge in certain lab configurations

Refuting / questioning sources:

No independent automotive-grade validation published; results are coin-cell scale, which systematically overstates performance vs. large-format pouch cells

Summary: Fast-charge results are from peer-reviewed academic work at coin-cell scale. Not yet validated in EV-grade large-format cells — that’s the purpose of the pilot line funded by Series A.

Claim: 10,000+ cycle life

Status: Partially verified (lab scale only)