Innovator: Leah Ellis

INNOVATION: From ancient Rome to present day, cement remains an essential building material, but its manufacturing accounts for approximately eight per cent of global CO2 emissions. Cement is traditionally made by heating a mixture of limestone, clay and sand in a coal-fired kiln to over 1400°C. Sublime Systems instead uses an electrochemical process to make cement at ambient temperature from a variety of abundant calcium sources. The result is a decarbonized cement that performs like the old standby and helps the construction industry commit to being net zero by 2050.

FOUNDATION: After earning a PhD in chemistry from Dr. Jeff Dahn’s lab at Dal, Dr. Ellis co-founded Sublime Systems in 2020 as a spin-out company from her postdoctoral work at the Massachusetts Institute of Technology (MIT). In January 2023, the company announced a $40 million injection of capital that will allow Sublime to grow its team, scale production and negotiate offtake agreements from customers. Sublime currently has the capacity to produce 100 tons of its low- carbon cement annually but plans to increase production to 40,000 tons per year by 2025.

INSPIRATION: During her time at Dal, Dr. Ellis remembers Professor Mary Anne White discussing cement’s outsized carbon footprint. The question of whether zero-carbon cement could become a cost- effective reality convinced her and MIT’s Dr. Yet-Ming Chiang to join forces and launch Sublime. “Through our expertise as battery scientists, we were able to find a solution by replacing a traditional thermal process with an electrochemical one,” says Dr. Ellis. “We approached the problem with determination and a creative mindset and were able to devise a breakthrough solution.”

WHY IT MATTERS: Decarbonized cement would keep the construction industry building while nations work toward meeting their climate goals. Sublime’s innovations were on display at last November’s COP27 in Egypt as part of a U.S. State Department exhibit showcasing firms whose technologies seek to reduce industrial CO2 emissions. “Low-carbon cement is critical to build a decarbonized economy,” says Dr. Ellis. “It’s ambitious, but we need to decarbonize the cement industry by 2050. We’re in a new industrial revolution where we need to redesign chemical processes in ways so that they aren’t harmful to the environment.”

This story appeared in the DAL Magazine Spring/Summer 2023 issue. Flip through the rest of the issue using the links below.