Xi Chen | Harvesting Energy Via Nanomechanics

Xi Chen
Associate Professor of Earth and Environmental Engineering
This profile is included in the publication Excellentia, which features current research of Columbia Engineering faculty members.
                                    Photo by Eileen Barroso

Every day around the world, an enormous amount of energy is wasted during power generation. The efficiency of fossil fuel power plants is about 40 percent and that of solar panels 25 percent, with the majority of the chemical and solar energies lost as low-grade heat. While scientists work on producing low-cost, efficient “clean” energy, 70 percent of the United States still relies on traditional carbon-based power and it is clear that, over the next few decades, we will still have to live with these traditional energy sources.

One researcher who may have found a way to harvest some of this lost energy through nanomechanics is Xi Chen. He is working with nanoporous materials, including nanoporous carbon, silica, and zeolite, materials that are readily available and low-cost, to convert ambient thermal or mechanical energy to electricity. The ultra-large specific pore surface area provides an ideal platform for energy conversion that yields unprecedented performance.

Chen has coupled nanoporous solids and functional liquids to create a multifunctional nanocomposite.

“Depending on the combination of the solid matrix and liquid filler, the thermomechanical and electrochemical processes amplified by the large surface area may enable high efficiency energy conversion among mechanical, thermal, and electrical energies,” he said.

The nanocomposite can simultaneously harvest electricity from the ambient lowgrade heat and/or mechanical motions. Significant power output—many times higher than other energy-harvesting materials—has already been successfully demonstrated by his group. Chen envisions that the integration of such a system into existing power plants would be relatively simple, requiring no major change, and the nanocomposite would generate “recovered” power as inexpensively as several cents per watt. He is currently in talking stages with several companies for implementing this technique.

Chen is also looking ahead, “not so far into the future,” he said, to multifunctional nanocomposite materials that could have broad, almost mind-boggling impacts: things like self-powered liquid armor that not only protects soldiers but also alleviates their battery needs, impact/blast-resistant skin for vehicles or aircraft whose shape will also morph to perform optimized functions, self- and wirelessly-powered sensors, among others. With these wide potential applications in aerospace, military, national security, and consumer areas, Chen is at the frontier of generating building blocks of intelligent materials for a smarter and more sustainable planet.

B.E., Xi’an Jiaotong University (P.R. China), 1994; M.E., Tsinghua University (P.R. China), 1997; S.M., Harvard, 1998; Ph.D., Harvard, 2001

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