An electroencephalography electrode based on a few-layer graphene/TiO2 nanotube nanoarchitecture for application in robot arm control

Scalp electroencephalogram (EEG) electrodes are non-invasive and directly connect the human brain with the external world; however, established dry and wet electrodes coated with conductive gels have the disadvantage of high scalp-contact resistance (Rscalp) and poor wearing comfort, respectively. In this study, a vertical few-layer graphene (FLG)/TiO2 nanotube array electrode combined with highly industrialized chemical vapor deposition and anodization technologies was developed to record EEG signals and control peripherals. The FLG/TiO2 electrode recorded scalp EEG signals in non-contact capacitive mode using a saturated aqueous NaCl solution or sweat as the electronic medium. The electrode can be worn quickly and comfortably, and the Rscalp placed in the hair area was only 13.4 kΩ; the spontaneous EEG had a high signal-to-noise ratio (SNR) of 76.8 dB with excellent stability in nearly 2 h of continuous use and a month of long-term use. In addition, the EEG electrode successfully recorded visually evoked EEG signals in non-training mode. For the 16 stimulation frequencies of the steady-state visually evoked potential, the electrode fed back the evoked EEG signals with an SNR of > 5.9 dB. Additionally, it allowed an online control robot arm to write letters with an average accuracy of 90.3%. The FLG/TiO2 electrode has the advantages of wearing comfort, low Rscalp, and excellent stability and is suitable for use in biological research and medical care, such as brain-controlled peripherals and long-term EEG collection for disabled people with impaired mobility. [Display omitted] •A few-layer graphene (FLG)/TiO2 nanotubes array-based scalp electrode was prepared.•The FLG/TiO2 electrode build stable conductive network and electrolytesweat balance.•The electroencephalology (EEG) electrode has low scalp contact resistance.•The FLG/TiO2 electrode recorded EEG signals in capacitive mode with a high signal-to-noise ratio.•The volunteers wearing the FLG/TiO2-based headband control robot arm to write letters.