Female Founders Series: Factorial Energy

For the first post of this series, we will focus on Factorial Energy, a Massachusetts solid-state battery company.

The CEO and founder is Dr. Siyu Huang. Her resume was impressive before she founded a battery company with $1B valuation, having both a Ph.D. and an M.B.A. from Cornell University.

Company Background

Factorial Energy, now located in Methuen, started as a side project while Dr. Huang worked at Johnson & Johnson and spun out of stealth mode in 2021. Previously the two founders (Dr. Siyu Huang and Dr. Alex Yu) started Lionano, and some of the patent portfolio originally started as Lionano patents. Lionano started in 2013 and spun out of the Cornell PhD program.

Lionano became Factorial Energy through a rebranding process. Specifically, Lionano split into two entities: Lionano Inc. (focused on cathodes) and Lionano SE Inc. (focused on solid-state batteries) in 2019. Lionano SE Inc. was rebranded as Factorial Energy in April 2021. Notably Dr. Alex Yu was CEO of Lionano and they switched during the rebrand with Dr. Siyu Huang as the CEO of Factorial.

Technical background

The Factorial website mentions two products: a “quasi-solid” electrolyte and a sulfide-based all-solid-state electrolyte.

Battery company websites can be helpful for customers and investors and non-technical people, but for juicy technical information the proof is in the patents.

Let’s dig in.

Based on the patent verbiage I can say that “quasi-solid electrolyte” means an electrolyte containing polymers and solvents not dissimilar to a gel electrolyte but still including excess solvent.

We have divided the Factorial patents into different segments: polymer containing electrolytes, anode-free, sulfide, cathode, and next-gen. We will start with their “quasi-solid electrolyte” or polymer containing electrolyte patents.

In 2019, Factorial filed a patent for electrolyte that now only has one remaining claim. Certainly makes my job easier.

“A polymer solid electrolyte synthesized by crosslinking a mixture comprising a lithium salt, a crosslinkable monomer, an ion dissociation compound, and an additive that can enhance capacity retention of an electrochemical device”

What about transference number of said electrolyte? If they are mentioning sulfide they are obviously attempting the holy grail of transference numbers (1 for those of you less nerdy than me). Transference number is the ratio of the current carried by a specific ion (in this case Li-ion) in an electrolyte solution relative to the total current. A transference number of 1 means the only current in the system is carried by Li+, love to see it, hard to achieve.

Factorial also has a patent for the electrochemical cells made with polymer electrolytes, and another for the electrodes for lithium-ion batteries.

Read more about Factorial’s patent portfolio here. 

TLDR: We found evidence in patents to back up both types of batteries, including a non-agyrodite sulfide-based electrolyte formula

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• If you’ve been thinking about starting your own company, this book should be the next on your list

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