Faradaic Energy Storage Research Articles

Capacitive vs Faradaic Energy Storage in a Hybrid Cell with LiFePO4/RGO Positive Electrode and Nanocarbon Negative Electrode

We report an advanced device based on a Nitrogen-doped Carbon Nanopipes (N-CNP) negative electrode and a lithium iron phosphate (LiFePO4) positive electrode. We carefully balanced the cell composition (charge balance) and suppressed the initial irreversible capacity of the anode in the round of few cycles. We demonstrated an optimal performance in terms of specific capacity 170 mAh/g of LiFePO4 with energy density of about 203 Wh kg−1 and a stable operation for over 100 charge−discharge cycles. The components of this device (combining capacitive and faradaic electrodes) are low cost and easily scalable. This device has a performance comparable to those offered by the present technology of LIBs with the potential for faster charging; hence, we believe that the results disclosed in this work may open up new opportunities for energy storage devices.

A redox-active 2D covalent organic framework with pyridine moieties capable of faradaic energy storage

A redox active pyridine based covalent organic framework was synthesized and used as an electrode in faradaic supercapacitors. The pyridine units in the DAP-COF undergo a reversible redox reaction, leading to an increase in specific capacitance relative to both its electroactive monomer and a COF lacking redox-active groups.

Hierarchical NiO–In2O3 microflower (3D)/ nanorod (1D) hetero-architecture as a supercapattery electrode with excellent cyclic stability

Simultaneous heterogeneous growth of one-dimensional nanorod supported three-dimensional microflower structures on nickel foam enhanced the non-capacitive faradaic energy storage performance due to the synergistic contribution from the hierarchical hybrid nanostructure.

Hybrid energy storage: the merging of battery and supercapacitor chemistries

The hybrid approach allows for a reinforcing combination of properties of dissimilar components in synergic combinations. From hybrid materials to hybrid devices the approach offers opportunities to tackle much needed improvements in the performance of energy storage devices. This paper reviews the different approaches and scales of hybrids, materials, electrodes and devices striving to advance along the diagonal of Ragone plots, providing enhanced energy and power densities by combining battery and supercapacitor materials and storage mechanisms. Furthermore, some theoretical aspects are considered regarding the possible hybrid combinations and tactics for the fabrication of optimized final devices. All of it aiming at enhancing the electrochemical performance of energy storage systems.

Fabrication and electrochemical capacitance of hierarchical graphene/polyaniline/carbon nanotube ternary composite film

A film composed of graphene (GN) sheets, polyaniline (PANI) and carbon nanotubes (CNTs) has been fabricated by reducing a graphite oxide (GO)/PANI/CNT precursor prepared by flow-directed assembly from a complex dispersion of GO and PANI/CNT, followed by reoxidation and redoping of the reduced PANI in the composite to restore the conducting PANI structure. Scanning electron microscope images indicate that the ternary composite film is a layered structure with coaxial PANI/CNT nanocables uniformly sandwiched between the GN sheets. Such novel hierarchical structure with high electrical conductivity perfectly facilitates contact between electrolyte ions and PANI for faradaic energy storage and efficiently utilizes the double-layer capacitance at the electrode–electrolyte interfaces. The specific capacitance of the GN/PANI/CNT estimated by galvanostatic charge/discharge measurement is 569 F g −1 (or 188 F cm −3 for volumetric capacitance) at a current density of 0.1 A g −1. In addition, the GN/PANI/CNT exhibits good rate capability (60% capacity retention at 10 A g −1) and superior cycling stability (4% fade after 5000 continuous charge/discharge cycles).