(Fe, Co) oxide nanowires on gold nanoparticles modified MOF-derived carbon nanoflakes for high-efficiency sodium-ion batteries and supercapacitors across electrolytes

The three-dimensional conductive porous carbon nanosheets (CPCN) are from the bimetallic metal-organic framework (MOFs) consisting of organic ligating groups that incorporate zinc and cobalt ions deposited onto a flexible carbon cloth (CC). Utilizing a hydrothermal approach, iron-cobalt oxide (FCO) nanowires are intricately embedded onto CPCN modified with gold (Au), forming a flexible FCO/Au/CPCN@CC electrode. The electrochemical characteristics of electrodes are evaluated in 1 M Na₂SO₄, supercapacitor's storage capacity is tested at 4 V using 1 M NaPF₆ electrolyte. Among its remarkable attributes are a peak energy density of 291.5 W h kg⁻¹ achieved at a power density of 153.85 W kg⁻¹, and even at the maximum power density of 1749.9 W kg⁻¹, it maintains 144.78 W h kg⁻¹. Undergoing 10,000 rounds of GCD, the equipment sustains a capacitance retention of 84.27 %. Moreover, the performance of the FCO/Au/CPCN@CC anode in sodium-ion batteries (SIBs) is assessed. At 0.1C, the discharge capacity reaches 958 mAh g⁻¹, and there is almost no loss after the rate cycle. The Coulomb efficiency surpasses 98 % during 500 cycles at a large C-rate. The integration of Au nanoparticles onto the CPNC surface enhances the energy storage characteristic of the FCO/Au/CPCN@CC composite material in both battery and supercapacitor applications.