Massively manufactured paper-based all-solid-state flexible micro-supercapacitors with sprayable MXene conductive inks

Abstract

Flexible micro-supercapacitors (FMSCs) are promising candidates for portable and on-chip energy storage due to their miniaturization, lightweight and high-security. Till now, FMSCs still suffer from several limitations, such as complex fabricating process, low areal energy storage, and short cycling lifetime, badly inhibiting its wider on-chip integrated applications. Here, we directly employ an easy-processing spray coating of the Ti3C2Tx MXene conductive inks to massively fabricate the paper-based all-solid-state FMSCs. Instead of traditional noble metals Au as current collector, the sprayable and highly conductive Ti3C2Tx MXene interdigitated electrodes serve the dual function of the active materials and current collection. Based on it, we develop an all-solid-state FMSC by employing polyvinyl alcohol & H2SO4 gel-like solid-state electrolyte and self-flowed polydimethylsiloxane encapsulated layer. With further optimizing the geometric configurations of interdigitated electrodes, the as-prepared FMSCs exhibit high areal capacitance of 23.4 mF cm−2 and excellent rate-capability of 81.4%. Moreover, these paper-based FMSCs also demonstrate outstanding cyclic capability of 92.4% capacitance retention after 5000 cycles, along with remarkable flexibility. Consequently, we believe that this innovative strategy will open new avenues for easily and largely fabricating various FMSCs to further promote the integration of portable and on-chip energy storage systems.