Laser-printed thick-film electrodes for solid-state rechargeable Li-ion microbatteries

Laser-printed thick-film electrodes (LiCoO2 cathode and carbon anode) are deposited onto metallic current collectors for fabricating Li-ion microbatteries. These microbatteries demonstrate a significantly higher discharge capacity, power and energy densities than those made by sputter-deposited thin-film techniques. This increased performance is attributed to the porous structure of the laser-printed electrodes, which allows improved ionic and electronic transport through the thick electrodes (~100 μm) without a significant increase in internal resistance. These laser-printed electrodes are separated by a laser-cut porous membrane impregnated with a gel polymer electrolyte (GPE) in order to build mm-size scale solid-state rechargeable Li-ion microbatteries (LiCoO2/GPE/carbon). The resulting packaged microbatteries exhibit a power density of ~38 mW cm−2 with a discharge capacity of ~102 μAh cm−2 at a high discharge rate of 10 mA cm−2. The laser-printed microbatteries also exhibit discharge capacities in excess of 2500 μAh cm−2 at a current density of 100 μA cm−2. This is over an order of magnitude higher than that observed for sputter-deposited thin-film microbatteries (~160 μAh cm−2).