To avoid being outpaced by the constant advancements in technology, lithium-ion batteries need to reduce
in size while simultaneously increasing in energy density. Both can be achieved by condensing the active
material in the batteries into ultra-thick electrodes, eliminating the need for repeated separators and
current collectors. Despite ultra-thick electrodes having an increased energy density, success has been
limited due to an increase in tortuosity of ionic diffusion routes. To eliminate this, our team has developed
a two-step femtosecond laser approach to increase the ionic conductivity of the cell and decrease the
diffusion distance. First, a femtosecond laser is used to create a microlattice structure, allowing a greater
surface area for the electrolyte to interact with the electrode. Then, the laser is used to ablate grooves into
the electrode surface to allow for interdigitated anodes and cathodes, greatly decreasing the ion transport
distance between electrodes. This laser structuring method is a viable solution for enabling high energy,
ultra-thick lithium-ion batteries.