Host‐Guest All‐in‐One Supercapacitors Enabled by 3D‐Printed Zwitterionic Gel Microlattices for Advanced Energy Storage

Abstract All‐in‐one supercapacitors (ASCs) are promising advanced energy storage devices for flexible and wearable electronics, owing to their high structural integration, superior mechanical stability, and simplified assembly process. However, conventional planar‐integrated ASCs often suffer from limited electrode loading, prolonged ion diffusion pathways, and poor low‐temperature tolerance. Herein, a customizable host‐guest 3D‐ASC is reported that effectively overcomes these limitations. A zwitterionic hydrogel electrolyte with a graded microlattice architecture is fabricated via direct ink writing 3D printing, enabling enlarged electrolyte‐electrode interfacial area and enhanced structural integrity. This architecture enables high active material loading without compromising ion transport efficiency. Simultaneously, the synergistic combination of zwitterionic polymers and water‐in‐salt components imparts ultrahigh ionic conductivity to the electrolyte, maintaining excellent performance even at −60 °C. The rationally designed host framework also facilitates in situ polymerization of polyaniline as the guest electrode, forming a continuous, integrated electrode‐electrolyte interface. As a result, the host‐guest 3D‐ASC achieves a 12‐fold enhancement in areal capacitance and energy density compared to planar ASCs, along with excellent rate capability, exceptional low‐temperature resilience, and long‐term cycling stability. This work demonstrates a robust and versatile strategy for next‐generation integrated energy storage devices with high energy density and environmental adaptability.