Dr. Maria Helena Braga

University of Porto, Portugal


Talk Title
A ferroelectric-electrolyte in various cell architectures
Talk Abstract

A ferroelectric material polarizes spontaneously. Its polarization can be reversed by an applied electric field. A ferroelectric contining dipoles and ions can store energy electrostatically in double layer capacitors and electrochemically through a chemical reaction. We have shown elsewhere that an alkali-metal electrode can be plated dendrite-free from a ferroelectric amorphous-oxide (glass) electrolyte having a room-temperature Li+ or Na+ conductivity σi ≈ 2.5´10-2 Scm-1 similar to that of a liquid electrolyte and low temperature conductivity of σi ≈ 10-2 Scm-1 at -20°C. The dielectric constant of the Li+-glass is εr ≈ 6×105 at -35°C. Here, we show various cell’ architectures that can be made with these ferroelectric electrolytes and that show much higher capacity and energy density than traditional batteries. Moreover, it is shown that the remanent polarization of the ferroelectric-electrolyte (polarization at zero potential) adds to the capacity of the cell and that these cells can be self-charged as long as certain conditions are observed.

Short Biography

Maria Helena Braga is a Solid-State Physicist which has a PhD in Materials Science and Engineering. She is an Associate Professor and the head of the Engineering Physics Department at FEUP-UPORTO.  From 2008-2011 she has worked in the Los Alamos Neutron Scattering Center, USA, as a Research Scholar and Long Term Visiting Staff Member and from 2016-2019 she worked as Senior Research Fellow at the University of Texas at Austin where she brought lithium and sodium ferroelectric glass-electrolytes and new architecture devices developed in Portugal and collaborated with Prof. John Goodenough in further developing these and other energy harvesting and storage devices.

Talk Keywords
Ferroelectric-electrolyte, harvesting and storage cells, electrostatic storage, self-charge.
Target Audience
Students, Post doctoral, Industry, Doctors and professors
Speaker-intro video

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