Material extrusion of electrochemical energy storage devices for flexible and wearable electronic applications

Additive manufacturing or 3D printing has witnessed significant growth in the past four decades and emerged as a revolutionizing technique for sustainable manufacturing. Among different additive manufacturing techniques, material extrusion (MEX) has recently been explored for the manufacturing of electrochemical energy storage devices (EESDs) for flexible and wearable electronics. It is attractive due to design freedom, easy processing of a wide range of materials, and user control. However, requirements of suitable ink rheology, post-processing, and strong adhesion between subsequent layers hinder its full utilization for flexible and wearable electronics manufacturing. This review presents the comprehensive state of art of the MEX fabricated batteries and supercapacitors for flexible and wearable electronics. The key parameters including ink rheology, surface consideration, MEX process parameters, performance analysis of MEX fabricated electrochemical devices, and materials required for different components have been critically reviewed. The commercial status and challenges of MEX fabricated EESDs for flexible and wearable applications are highlighted, and recommendations are provided for further improvement MEX fabricated EESDs for flexible and wearable applications.