Making better batteries : local chemical concentration gradient manipulation with ultrasound to prevent dendrite growth during electroplating

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dc.contributor Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta fi
dc.contributor University of Helsinki, Faculty of Science en
dc.contributor Helsingfors universitet, Matematisk-naturvetenskapliga fakulteten sv
dc.contributor.author Malinen, Henri
dc.date.issued 2021
dc.identifier.uri URN:NBN:fi:hulib-202105102096
dc.identifier.uri http://hdl.handle.net/10138/329721
dc.description.abstract Dendrite prevention can be achieved by manipulating the local chemical concentration gradient by ultrasound. An ultrasonic field, which generates acoustic streaming, can manipulate the ionic flux at the electrode surface by altering the local ion concentration gradient at said surface according to the streaming pattern. The pattern is determined by the ultrasonic field and the geometry of the sonication volume. The preventive action can be directed to an arbitrary point on the surface, or be swept across it to achieve a smoother electroplating. Dendritic growth is concentrated to areas of higher concentration gradient. This is because at the electrode surface both the electric and convective fluxes tend to zero. If the reduction of ions into their metallic form is fast enough, the metal layer growth rate is determined by the diffusive flux, which is determined by the ion concentration gradient and the diffusion constant of the ion in the electrolyte. In this study, tin was used as the transported ion instead of lithium for safety reasons. A custom-made battery mockup cell was constructed for the experiments. The anode was imaged with a usb microscope camera to determine the growth of the dendrites during the process. The electroplating current and piezo driving power were varied between 100 mA to 275 mA and 0 to 6.6 W, respectively. With piezo driving electrical power less than 10 W, it was possible to lower the maximum lengths of dendrites. Finite element method simulations were conducted to validate the hypothesis and experimental results. This ultrasonic method could be used to allow rechargeable, lightweight, high capacity lithium metal batteries. The piezos could be integrated into battery chargers. en
dc.language.iso eng
dc.publisher Helsingin yliopisto fi
dc.publisher University of Helsinki en
dc.publisher Helsingfors universitet sv
dc.subject Dendrites
dc.subject Litihum battery
dc.subject Electroplating
dc.subject Ultrasound
dc.title Making better batteries : local chemical concentration gradient manipulation with ultrasound to prevent dendrite growth during electroplating en
dc.type.ontasot pro gradu -tutkielmat fi
dc.type.ontasot master's thesis en
dc.type.ontasot pro gradu-avhandlingar sv
dct.identifier.urn URN:NBN:fi:hulib-202105102096
dc.subject.specialization Elektroniikka ja teollisuusfysiikka fi
dc.subject.specialization Electronics and Industrial Physics en
dc.subject.specialization Elektronik och industrifysik sv
dc.subject.degreeprogram Materiaalitutkimuksen maisteriohjelma fi
dc.subject.degreeprogram Master's Programme in Materials Research en
dc.subject.degreeprogram Magisterprogrammet i materialforskning sv

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