Symposium BM08: Materials-to-Devices for Integrated Wearable Systems—Energy Harvesting and Storage, Sensors/Actuators and Integration

Philipp Simmons, Massachusetts Institute of Technology

All-Solid-State Glucose Fuel Cell for Energy Harvesting in the Human Body

Written by Daniel Gregory

Wearable devices and implants within the human body require a reliable source of power. Fuel cells operating through the oxidation of glucose to gluconic acid are an attractive option; however, current devices predominantly use polymer membranes or liquid electrolytes to separate the membranes. This leads to immense challenges with rapid degradation, unpredictability, and an inability to miniaturize the system, leading to insufficient power density. Philipp Simmons introduced an all solid-state glucose fuel cell using a solid ceria membrane and a porous platinum catalyst. The materials are all biocompatible and provide a high power density, and the device is fabricated on silicon for easy integration to other devices.

A key challenge when fabricating these devices was the mechanical stress imposed by the pulsed laser deposition (PLD) of the ceria. By lowering the background pressure in the PLD system, Simmons found that the microstructure of the ceria changed, with grain sizes increasing as the film grew away from the silicon substrate, reducing strain. The novel microstructure also improved device performance due to the ceria now becoming nanoporous. Simmons then explained the mechanism of proton transport in ceria and the way in which the device was able to confirm this, before concluding with a detailed presentation of the device performance. Of note was the high current density even in unengineered devices, and a record high cell potential nearly triple current literature values. More work is being done by the group to determine the causes for this and further optimize the device performance.