Electrical engineering

Physics

Electrode

Organic chemistry

Electric double-layer capacitor

Hydrogen

Capacitor

Specific energy

Capacitive coupling

Energy storage

Electrolytic capacitor

Engineering

Voltage

Physical chemistry

Power (physics)

Chemistry

Materials science

Quantum mechanics

Electrolyte

Capacitance

Chemical engineering

Optoelectronics

Supercapacitor

Nature Communications

Conventional electric double-layer capacitors are energy storage devices with a high specific power and extended cycle life. However, the low energy content of this class of devices acts as a stumbling block to widespread adoption in the energy storage field. To circumvent the low-energy drawback of electric double-layer capacitors, here we report the assembly and testing of a hybrid device called electrocatalytic hydrogen gas capacitor containing a hydrogen gas negative electrode and a carbon-based positive electrode. This device operates using pH-universal aqueous electrolyte solutions (i.e., from 0 to 14) in a wide temperature range (i.e., from - 70 °C to 60 °C). In particular, we report specific energy and power of 45 Wh kg-1 and 458 W kg-1 (both values based on the electrodes' active materials mass), respectively, at 1 A g-1 and 25 °C with 9 M H3PO4 electrolyte solution. The device also enables capacitance retention of 85% (final capacitance of about 114 F g-1) after 100,000 cycles at 10 A g-1 and 25 °C with 1 M phosphate buffer electrolyte solution.

Production of a hybrid capacitive storage device via hydrogen gas and carbon electrodes coupling