Flexible Lithium Ion Rechargeable Battery with Large Scale Interdigitated Electrodes

On the advent of flexible devices, developing thin and flexible lithium-ion batteries (FLB) becomes a requisite for full flexible electronic application.  Here, we contrived a co-planar type thin and flexible Lithium ion battery by using the design concept of interdigitated electrodes. Whereas a conventional LIB has its components in layer by layer structures, the co-planar type lithium ion battery has the interdigitated structure of positive and negative electrodes on the same plane without a separator, which possibly leads to a thinner battery thickness and stress relieved electrode structure. Unlike previous co-planar type microbatteries, we fabricated pouch cell type batteries with large scale interdigitated electrode structures (~ mm dimension scale) using conventional electrode materials. Our electrochemical tests showed the energy density per cathode area of ~ 1.4 mAh/cm² and the specific capacity of cathode of 93.61 mAh/g after the cycle test up to 300, which successfully demonstrated the feasibility of a co-planar design pouch cell LIB with the interdigitated electrodes. Furthermore, our mechanical bending test results showed that the co-planar-type battery is mechanically stable during 4000 bending cycles with a bending radius of 1/8 inch.