▎ 摘　　要

Convenient integration of high-purity graphene film on industrial-sized silicon wafer is highly desired for onchip electronics such as pulse energy harvesting capacitors. However, current graphene materials usually need costly additional purification procedures to remove metallic impurities before use. Herein, a purification-integration technique is explored for graphene oxide (GO) by using the reverse migrations of metal ions and negatively charged GO sheets in water under electric fields, and corresponding films are successfully deposited on 6-inch anodic silicon wafers in one step. Nearly similar to 90% of metallic impurities (e.g., Fe, Mn, and Cr) could be removed for the electric-field purified reduced graphene oxide film (EPGF) with the content of Cr as low as similar to 10 ppm. Owing to the high purity and the robust interface contact to silicon substrates, the EPGF as capacitor electrodes delivered the minimal self-discharging current of similar to 0.11 mu A and the highest working frequency of 18420.7 Hz (i.e., up to 10 kHz-level at -73.5 degrees) for graphene capacitors reported to date, as well as maintaining normal areal capacitance. In contrast to the common strategy by increasing ion rate, this study focuses on the improvement of electron rate by optimizing electronic interface contact, which provides new insights for fabricating kilohertz graphene capacitors.