Optimized printed cathode electrodes for high performance batteries

Abstract

Increasing mobility, sensing, and interconnection needs is driving the need for low cost and environmental friendly energy storage systems, and therefore, printed batteries represent one of the most appealing solutions. To identify materials‐processing conditions–performance relationships to design improved screen‐printed batteries, the effects of the ink preparation method and the chemical structure of the polymer binder on batteries performance are studied. Screen‐printed cathodes with “green” solvent cyclopentyl methyl ether (CPME) are produced using different styrene‐block‐copolymers (SBC) with different ethylene/butylene ratios and using three dispersion methods of the cathode components. It is shown that a limited amount of ethylene in the copolymer binder enhances the discharge capacity for 5C and C/5 rates (105 and 142 mAh g−1, respectively). The ink preparation methods affect cathode performance in a larger extent than the chemical structure of the binder. The sequential addition of active and conductive materials to the styrene–ethylene/butylene–styrene solution results in a higher cathode charge/discharge capacity compared with the other explored dispersion methods (150/147 mAh g−1 for charge/discharge capacity). The optimized cathode performance is related with the improved degree of dispersion of the cathode components, as assessed by rheological properties of inks and by the morphological characterization of the printed cathodes