1：Experimental Design and Method Selection:

Nano-sized magnetite powders with addition of iron nitrides were synthesized via pulsed laser ablation (PLA) of an iron target in atmospheric air. A series of iron oxide nanopowders with various phase compositions and structures were prepared via heat treatment of the initial powder at temperatures in the range 200–500°C.

2：Sample Selection and Data Sources:

The powders were introduced into the composition of carbon paste electrodes (CPEs). The capacitive characteristics of the electrodes prepared were studied in comparison to a commercial electroexplosive iron oxide powder.

3：List of Experimental Equipment and Materials:

Nd:YAG LS-2131M-20 (LOTIS TII) laser, SNOL

4：7/1100 muffle furnace, HT-7700 (Hitachi) microscope, Vega 3H (Tescan) microscope, TriStar II 3020 (Micromeritics) gas-adsorption specific surface and porosity analyzer, P8-nano (Electrochemical Instruments) potentiostat-galvanostat. Experimental Procedures and Operational Workflow:

The ablation process lasted 5 h. Then, the product powder was mechanically removed from the reactor. The average nanopowder yield for the set experimental parameters was 15 mg/h. The thus-produced material was denoted Fe/in. Then, the powder was heat-treated in a SNOL 6.7/1100 muffle furnace at four temperatures from the range 200–500°С (4 h; heating rate: 10 K/min).

5：7/1100 muffle furnace at four temperatures from the range 200–500°С (4 h; heating rate:

5. Data Analysis Methods: The specific capacitance С (F/g) was calculated from the charge–discharge current in cyclic voltammograms recorded at the potential scan rate 10 mV/s.