S. Wang, L.M. Li, S.H. Zheng, P. Das, X.Y. Shi, J.X. Ma, Y. Liu, Y.Y. Zhu, Y. Lu*, Z.-S. Wu*and H.-M. Cheng*

National Science Review, 2023, nwac271.

DOI: 10.1093/nsr/nwac271 [PDF]

Monolithic integrated micro-supercapacitors (MIMSCs) with high systemic performance and cell number density are important for miniaturized electronics to empower the Internet of Things.However, fabrication of customizable MIMSCs in an extremely small space remains a huge challenge considering key factors like materials selection, electrolyte confinement, microfabrication, and device-performance uniformity. Here, we develop a universal and large throughput microfabrication strategy to address all these issues by combining multi-step lithographic patterning, spray printing of MXene microelectrodes and controllable three-dimensional (3D) printing of gel electrolytes. We achieve the monolithic integration of electrochemically isolated micro-supercapacitors in closely proximity by leveraging high-resolution micropatterning techniques for microelectrode deposition and 3D printing for precise electrolyte deposition. Notably, the MIMSCs obtained demonstrate a high areal number density of 28 cells cm^-2(340 cells on 3.5×3.5 cm²), a record areal output voltage of 75.6 V cm^-2, an acceptable systemic volumetric energy density of 9.8 mWh cm^-3, and an unprecedentedly-high capacitance retention of 92% after 4000 cycles at an extremely high output voltage of 162 V. This work paves the way for monolithic integrated and microscopic energy storage assemblies for powering future microelectronics.