Graphene-based in-plane micro-supercapacitors with high power and energy densities

TLDR

Micro‑supercapacitors are essential on‑chip power sources, yet their power and energy densities still lag behind electrolytic capacitors and lithium thin‑film batteries, and in‑plane geometries hold promise for miniaturized and flexible electronics. The authors aim to develop graphene‑based in‑plane interdigital micro‑supercapacitors that achieve ultrahigh power and energy densities. They fabricate these devices on arbitrary substrates using graphene interdigital electrodes. The resulting micro‑supercapacitors exhibit an area capacitance of 80.7 µF cm⁻², a stack capacitance of 17.9 F cm⁻³, a power density of 495 W cm⁻³—higher than electrolytic capacitors—and an energy density of 2.5 mWh cm⁻³ comparable to lithium thin‑film batteries, with superior cycling stability and ultrahigh charge‑discharge rates up to 1,000 V s⁻¹. The study is authored by Wu et al.

Abstract

Micro-supercapacitors are important on-chip micro-power sources for miniaturized electronic devices. Although the performance of micro-supercapacitors has been significantly advanced by fabricating nanostructured materials, developing thin-film manufacture technologies and device architectures, their power or energy densities remain far from those of electrolytic capacitors or lithium thin-film batteries. Here we demonstrate graphene-based in-plane interdigital micro-supercapacitors on arbitrary substrates. The resulting micro-supercapacitors deliver an area capacitance of 80.7 μF cm−2 and a stack capacitance of 17.9 F cm−3. Further, they show a power density of 495 W cm−3 that is higher than electrolytic capacitors, and an energy density of 2.5 mWh cm−3 that is comparable to lithium thin-film batteries, in association with superior cycling stability. Such microdevices allow for operations at ultrahigh rate up to 1,000 V s−1, three orders of magnitude higher than that of conventional supercapacitors. Micro-supercapacitors with an in-plane geometry have great promise for numerous miniaturized or flexible electronic applications. Micro-supercapacitors offer the advantage of high power density over lithium batteries and high energy density over electric capacitors, but integration of these advantages is yet to be achieved. Wu et al. develop a graphene-based in-plane micro-supercapacitor with ultrahigh power and energy densities.