3D printed architecture of Li ion batteries and its applications to smart wearable electronic devices
Abstract The evolution of wearable electronics technology, currently used in various smart wearable devices such as watches and eyeglasses based on applications that range from healthcare to fashion, has provided customers an access to data directly from these devices. From the energy consumption point of view, several challenges are yet to be addressed. However, the conventional Li ion batteries (LIBs) are confined to particular shapes and sizes that limit their incorporation into certain wearable device applications. This study proposes a highly efficient 3D printing technology for fabricating printed LIBs of any shape suitable for a wide range of wearable devices. In particular, the proposed technology is based on modulating inks containing active materials, conductive additives, and binders to obtain a non Newtonian fluid for achieving a homogeneous flow of the inks through the printer nozzle. The individually printed electrodes and separator membranes are assembled and sealed in a plastic sheet with the injection of a small electrolyte for membrane soaking. All printed LIBs display a specific discharge capacity of 184 mAh g 1 at a current rate of 0.1 C and maintained a consistent electrochemical performance upon bending. This promising technology can be adopted for the fabrication and integration of batteries for future wearable devices.