Low-crystalline iron oxide hydroxide nanoparticle anode for high-performance supercapacitors

Abstract

Carbon materials are generally preferred as anodes in supercapacitors; however, their low capacitance limits the attained energy density of supercapacitor devices with aqueous electrolytes. Here, we report a low-crystalline iron oxide hydroxide nanoparticle anode with comprehensive electrochemical performance at a wide potential window. The iron oxide hydroxide nanoparticles present capacitances of 1,066 and 716 F g−1 at mass loadings of 1.6 and 9.1 mg cm−2, respectively, a rate capability with 74.6% of capacitance retention at 30 A g−1, and cycling stability retaining 91% of capacitance after 10,000 cycles. The performance is attributed to a dominant capacitive charge-storage mechanism. An aqueous hybrid supercapacitor based on the iron oxide hydroxide anode shows stability during float voltage test for 450 h and an energy density of 104 Wh kg−1 at a power density of 1.27 kW kg−1. A packaged device delivers gravimetric and volumetric energy densities of 33.14 Wh kg−1 and 17.24 Wh l−1, respectively.

The way to improve the energy density of supercapacitors: Progress and perspective

“…Other materials can be used as the other electrode to fabricate ASCs, such as porous carbon [50]. For example, ASCs employing aqueous electrolytes have potential windows of greater than 2.0 V. The energy density of ASCs can reach almost 100 W h kg −1 [51][52][53]. Based on these aforementioned features, a higher ASC energy density can be obtained by utilizing organic or ionic-liquid electrolytes, which have higher working voltages.…”

Utilizing Waste Thermocol Sheets and Rusted Iron Wires to Fabricate Carbon–Fe3O4 Nanocomposite‐Based Supercapacitors: Turning Wastes into Value‐Added Materials

“…[2,3] Pseudocapacitors, in which charges torage is achieved through Faradic redox reactions, provide significantly highere nergy densities, but usually suffer from lower cyclic stability. [4,5] Typical ASCs incorporate electrodes fabricated with iron-containing oxides (such as Fe 2 O 3 ,F e 3 O 4 ,Z nFe 2 O 4 ,a nd NiFe 2 O 4 )a se lectrode mate-rials, [6][7][8][9] which show high capacitance and energy density values, butthese metal oxidesusually have poor electrical conductivity anda re hydrophobic in nature. [4,5] Typical ASCs incorporate electrodes fabricated with iron-containing oxides (such as Fe 2 O 3 ,F e 3 O 4 ,Z nFe 2 O 4 ,a nd NiFe 2 O 4 )a se lectrode mate-rials, [6][7][8][9] which show high capacitance and energy density values, butthese metal oxidesusually have poor electrical conductivity anda re hydrophobic in nature.…”

Polypyrrole Nanopipes as a Promising Cathode Material for Li‐ion Batteries and Li‐ion Capacitors: Two‐in‐One Approach

“…LIBs are well‐known for high energy density (around 150–200 Wh/kg), however batteries exhibit poor power as well as cyclic stability. Conversely, SCs show high power density (2–5 kW/kg) and excellent cycling stability devices but suffer of low energy density . Therefore, it is desirable to combine the advances of both LIBs and SCs in a single device to develop high performance hybrid energy storage devices.…”