3D-printed cobalt hexacyanoferrate-based asymmetric micro-supercapacitors with ultrahigh areal energy density

Abstract

The rapid evolution of miniaturized portable and wearable electronics has significantly intensified the demand for miniature energy storage devices featuring high energy density, cost-effective fabrication, and scalable manufacturing. 3D printing of energy storage electrodes provides new possibilities for meeting these emerging needs. Herein, we present the development of 3D-printed planar asymmetric quasi-solid-state micro-supercapacitors (MSCs) with high areal energy density, utilizing cobalt hexacyanoferrate (CoHCF) as the positive electrode and activated carbon (AC) as the negative electrode. The as-prepared MSCs exhibit a broad operating potential window of 1.5 V and exceptional areal energy and power densities of 415.8 μWh cm⁻² and 7.5 mW cm⁻², respectively, along with an impressive cycling retention rate of 104.9 % even after 15,000 cycles. Furthermore, the printed MSCs display excellent deformation-tolerant ability and integrability. These results highlight the potential of CoHCF//AC asymmetric MSCs as promising candidates for miniature, flexible, and integrable energy storage applications.