Engineering topics
McKelvey, Kim
Publications and source records attributed to McKelvey, Kim.
Redox cycling in nanogap electrochemical cells
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Microscale 2.5D Batteries
3D solid-state batteries use vertical topography to increase both energy and power density relative to batteries with planar geometry. Here we investigate, using finite element simulations, a battery that incorporates a 3D cathode consisting of a vertical array of microcolumns, and a planar 2D anode, which we call a 2.5D battery. By confining the 3D structure to the cathode we greatly simplify the battery fabrication process (i.e., 3D structure only needs to be introduced into one electrode) at the cost of introducing a non-uniform electrolyte thickness in which the anode-cathode distance varies significantly across different parts of the battery. We use simulations to show that a non-uniform electrolyte thickness results in inhomogeneous lithiation and subsequent underutilization of the cathode. The underutilization of the cathode can be avoided by using an electrolyte with sufficient ionic conductivity, which suggests that non-uniform electrolyte thickness can be tolerated in high ionic conductivity electrolytes but should be avoided in low ionic conductivity electrolytes.
Fabrication, testing and simulation of all solid state three dimensional Li-ion batteries
Realization of safe, long cycle life and simple to package solid-state rechargeable batteries with high energy and power density has been a long-standing goal of the energy storage community. [1,2] Much of the research activity has been focused on developing new solid electrolytes with high Li ionic conductivity. In addition, LiPON, the only solid electrolyte currently used in commercial thin film solid state Li-ion batteris (SSLIBs), has a conductivity of ~10 -6 S/cm, compared to ~0.01 S/cm typically observed for liquid organic electrolytes [3] .