Conducting polymers-based electrochemical supercapacitors—Progress and prospects

Hierarchical porous carbon aerogel derived from bagasse for high performance supercapacitor electrode

Renewable, cost-effective and eco-friendly electrode materials have attracted much attention in the energy conversion and storage fields. Bagasse, the waste product from sugarcane that mainly contains cellulose derivatives, can be a promising candidate to manufacture supercapacitor electrode materials. This study demonstrates the fabrication and characterization of highly porous carbon aerogels by using bagasse as a raw material. Macro and mesoporous carbon was first prepared by carbonizing the freeze-dried bagasse aerogel; consequently, microporous structure was created on the walls of the mesoporous carbon by chemical activation. Interestingly, it was observed that the specific surface area, the pore size and distribution of the hierarchical porous carbon were affected by the activation temperature. In order to evaluate the ability of the hierarchical porous carbon towards the supercapacitor electrode performance, solid state symmetric supercapacitors were assembled, and a comparable high specific capacitance of 142.1 F g(-1) at a discharge current density of 0.5 A g(-1) was demonstrated. The fabricated solid state supercapacitor displayed excellent capacitance retention of 93.9% over 5000 cycles. The high energy storage ability of the hierarchical porous carbon was attributed to the specially designed pore structures, i.e., co-existence of the micropores and mesopores. This research has demonstrated that utilization of sustainable biopolymers as the raw materials for high performance supercapacitor electrode materials is an effective way to fabricate low-cost energy storage devices.

LiMnBO₃ nanobeads as an innovative anode material for high power lithium ion capacitor applications

A novel approach was made to fabricate lithium ion hybrid capacitor (Li-HC) having LiMnBO3 nanobead (LMB-NB) anode and polyaniline nanofiber (PANI) cathode in 1 M LiPF6 organic electrolyte. LMB-NB and PANI nanofibers were synthesized using urea assisted microwave-solvothermal method and chemical polymerization process, respectively. The PANI/LMB-NB cell showed improved electrochemical capacitive behavior as compared to activated carbon (AC)/LMB-NB cell due to the characteristic conductivity and the morphological feature of PANI as well as LMB-NB electrodes. A discharge capacitance (DCcell) of ∼125 F g(-1) was obtained at a current density of 1 A g(-1) between the potential range 0 and 3 V for PANI/LMB-NB cell, while AC/LMB-NB cell delivered only 77 F g(-1) at the same current density. Moreover, PANI/LMB-NB cell exhibited excellent rate performance with the DCcell of about 55 F g(-1) at 2.25 A g(-1) and still retained 94% of the initial value after 30 000 charge-discharge cycles. In addition, maximum energy and power densities of 42 Wh kg(-1) and 5350 W kg(-1), respectively, were achieved from PANI/LMB-NB cell. The obtained DCcell, energy, and power densities along with prolonged cyclic life for PANI/LMB-NB cell are some of the best ever reported values for Li-HC as compared to the cells constructed with various lithium intercalating materials.

Novel hybrid micro-supercapacitor based on conducting polymer coated silicon nanowires for electrochemical energy storage

The development of a novel hybrid symmetric micro-supercapacitor based on poly(3,4-ethylenedioxythiophene) coated silicon nanowires using an ionic liquid PYR₁₃TFSI as an electrolyte has been demonstrated.

The effect of the carbon surface chemistry and electrolyte pH on the energy storage of supercapacitors

Combined effect of electrolyte pH and surface chemistry of oxidized carbon xerogels on the electrochemical response of supercapacitors.