Recent progress and challenges in interdigital microbatteries: Fabrication, functionalization and integration

Currently, the increasing demands for portable, implantable, and wearable electronics have triggered the interest in miniaturized energy storage devices. Different from conventional energy storage devices, interdigital microbatteries (IMBs) are free of separators and prepared on a single substrate, potentially achieving a short ionic diffusion path and better performance. Meanwhile, they can be easily fabricated and integrated into on-chip miniaturized electronics, holding the promise to provide long-lasting power for advanced microelectronic devices. To date, while many seminal works have been reviewed the topic of microbatteries, there is no work that systematically summarizes the development of IMBs of high energy density and stable voltage platforms from fabrication, functionalization to integration. The current review focuses on the most recent progress in IMBs, discussing advanced micromachining techniques with compatible features to construct high-performance IMBs with smart functions and intelligent integrated systems. The future opportunities and challenges of IMBs are also highlighted, calling for more efforts in this dynamic and fast-growing research field.