Affiliation:
1. Micro and Nanostructured Materials Laboratory – NanoLab Department of Energy Politecnico di Milano via Ponzio 34/3 20133 Milano Italy
2. Electron Spectroscopy and Nanoscopy Istituto Italiano di Tecnologia via Morego 30 16163 Genova Italy
3. Solid Liquid Interface Nano-Microscopy and Spectroscopy (SoLINano-Σ) lab Department of Physics Politecnico di Milano Piazza Leonardo da Vinci 32 20133 Milano Italy
Abstract
AbstractIn pulsed laser deposition, along the traditionally exploited deposition on the front‐side of the plasma‐plume, a coating forms on the surface of the target as well. For reproducibility, this residue is usually cleaned and discarded. Here we instead investigate the target‐side coated materials and employ them as a binder‐free supercapacitor electrode. The ballistic‐aggregated, target‐side nanofoam is compact and features a larger fraction of sp2‐carbon, higher nitrogen content with higher graphitic‐N and lower oxygen content with fewer COOH groups than that of diffusive‐aggregated conventional nanofoams. They are highly hydrogenated graphite‐like amorphous carbon and superhydrophilic. The resulting symmetric micro‐supercapacitor delivers higher volumetric capacitance of 522 mF/cm3 at 100 mV/s and 104 % retention after 10000 charge‐discharge cycles over conventional nanofoam (215 mF/cm3 and 85 % retention) with an areal capacitance of 134 μF/cm2 at 120 Hz and ultrafast frequency response. Utilizing the normally discarded target‐side material can therefore enable high performing devices while reducing waste, cost and energy input per usable product, leading towards a greater sustainability of nanomaterials synthesis and deposition techniques.