Electrochemically driven mechanical energy harvesting
Author(s)Kim, Sangtae; Choi, Soon Ju; Zhao, Kejie; Yang, Hui; Gobbi, Giorgia; Zhang, Sulin; Li, Ju; ... Show more Show less
MetadataShow full item record
Efficient mechanical energy harvesters enable various wearable devices and auxiliary energy supply. Here we report a novel class of mechanical energy harvesters via stress–voltage coupling in electrochemically alloyed electrodes. The device consists of two identical Li-alloyed Si as electrodes, separated by electrolyte-soaked polymer membranes. Bending-induced asymmetric stresses generate chemical potential difference, driving lithium ion flux from the compressed to the tensed electrode to generate electrical current. Removing the bending reverses ion flux and electrical current. Our thermodynamic analysis reveals that the ideal energy-harvesting efficiency of this device is dictated by the Poisson’s ratio of the electrodes. For the thin-film-based energy harvester used in this study, the device has achieved a generating capacity of 15%. The device demonstrates a practical use of stress-composition–voltage coupling in electrochemically active alloys to harvest low-grade mechanical energies from various low-frequency motions, such as everyday human activities.
DepartmentMassachusetts Institute of Technology. Department of Materials Science and Engineering; Massachusetts Institute of Technology. Department of Mechanical Engineering; Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Nature Publishing Group
Kim, Sangtae, Soon Ju Choi, Kejie Zhao, Hui Yang, Giorgia Gobbi, Sulin Zhang, and Ju Li. “Electrochemically Driven Mechanical Energy Harvesting.” Nat Comms 7 (January 6, 2016): 10146.
Final published version