Efficient 3D Printed Pseudocapacitive Electrodes with Ultrahigh MnO2 Loading

Abstract

Retaining sound electrochemical performance of electrodes at high mass loading holds significant importance to energy storage. Pseudocapacitive materials such as manganese oxide (MnO2) deposited on current collectors have achieved outstanding gravimetric capacitances, sometimes even close to their theoretical values. Yet, this is only achievable with very small mass loading of active material typically less than 1 mg cm-2. Increasing mass loading often leads to drastic decay of capacitive performance due to sluggish ion diffusion in bulk material. In this talk, I will demonstrate a 3D printed macroporous graphene aerogel electrode with MnO2 loading of 182.2 mg cm-2, which achieves a record-high areal capacitance of 44.13 F cm-2. The engineered porous structure allows efficient ion diffusion and therefore enables the ultrahigh mass loading of pseudocapacitive materials without sacrificing their gravimetric and volumetric capacitive performance. Most importantly, this 3D printed graphene aerogel/MnO2 electrode can simultaneously achieve excellent capacitance normalized to area, gravimetry, and volume, which is the trade-off for most electrodes. This work successfully validates the feasibility of printing practical pseudocapacitive electrodes, which might innovate the conventional layer-by-layer stacking fabrication process of commercial supercapacitors. Figure 1