Chocolate pattern-inspired flexible thick electrodes: A facile mechanical imprinting method

Inspired by chocolate patterning, this paper proposes a facile mechanical imprinting method for constructing novel flexible thick electrodes in response to the rapid development of multifunctional batteries. Appropriately designed imprinting of the active layer in a semi-dry state during the drying process can introduce stable ridge-slot patterns within the thick electrodes, which requires only low-cost and scalable templates with minimal modifications to the electrode fabrication process. Due to imprinting introducing ion transport channels in the electrode thickness direction, electrochemical cycling performance of imprinted thick electrodes can be significantly enhanced compared to conventional thick electrodes. For high C-rate conditions, the areal capacity of the thick electrode can be increased by up to approximately 225 % due to the imprinting, while the cycling remains stable. More interestingly, these thick electrodes with ridge-slot patterns exhibit remarkable flexibility due to the fact that the slot portion acts as a “joint”. The capacity loss of a pouch cell containing the imprinted electrode loses only about 4 % of its capacity after 10,000 bending cycles. Based on these results, this work provides a novel pathway for the development of flexible thick electrodes for multifunctional high-capacity batteries.