Limitations and Recent Advances in High Mass Loading Asymmetric Supercapacitors Based on Pseudocapacitive Materials

Zero-discharge, self-sustained 3D-printed microbial electrolysis cell for biohydrogen production: a review

Microbial fuel cell (MFC) and microbial electrolysis cell (MEC) technologies have been used recently in bench-scale bioenergy (electricity) generation, biohydrogen (H2) production, biosensing, and wastewater treatment. There are still a lot of obstacles to overcome in terms of commercialization and industrial settling. These difficulties include lengthy start-up times, intricate reactor designs for managing large reaction volumes, and expensive and time-consuming large-scale system fabrication procedures. Interestingly, combining three-dimensional (3D) printing with MFC and MEC technology appears to be a workable and promising way to get past these obstacles. Moreover, a rapid start-up with no delays in the current generation using MFC and MEC is possible with 3D printed bio-anodes. Furthermore, H2 can be generated from wastewater by powering a stacked MFC and MEC-coupled with electrochemical capacitor (ECC) system using 3D printing technology. To the best of the author's knowledge, this review paper is the first to explicitly highlight the use of 3D printing in creating a stacked MFC-ECC-MEC system in conjunction with a photobioreactor (PBR) to produce significant quantities of H2 and carbon dioxide (CO2) can be utilized for algae production. A notable feature of 3D printing technology is its reliable production capabilities, enabling MFC-ECC-MEC-PBR systems to be expanded by setting up numerous stacks of MFC-ECC-MEC-PBR units devoid of material waste and human error. The present review attempts to provide an update on the current status of the 3D printing application, that is meant to propel the MFC-ECC-MEC-PBR system forward.

Hierarchical Nanoporous Carbons with an Integrated Activation Using 3D Flower-Like ZnO Microspheres and KOH for Flexible EDL Capacitor with a High Operating Potential

Activated nanoporous carbons are widely used in various applications, where their efficiency is largely determined by their specific surface area and pore structure. Traditional KOH-assisted chemical activation methods primarily produce micropores, limiting the performance of these porous carbons in applications requiring a hierarchical arrangement of micro, meso, and macropores. This study introduces a novel integrated activation strategy using 3D flower-like microsphere (3DFM) ZnO and KOH to synthesize nanoporous carbons from Sesbania Grandiflora side shoots. The porous nanosheet tips and microsphere bulk of 3DFM-ZnO generate mesopores and macropores, while KOH induces microporosity, resulting in a hierarchical structure with an ultrahigh specific surface area of 4114 m2 g-1. The fabricated activated carbon electrodes with the combination of macro, meso, and micropores exhibit high specific capacitances of 672 F g-1 for the positive electrode and 756 F g-1 for the negative electrode. The performance of electrodes is optimized with the proper selection of electrolytic ions for positive and negative electrodes. A high operating potential window of 2.7 V is achieved in a symmetric device through charge-balanced mass loading. The fabricated flexible electric double-layer capacitor demonstrates a maximum specific energy of 128.2 W h kg-1 at a specific power of 1.35 kW kg-1.

Surfactant-assisted preparation of all-gel-state flexible supercapacitor with remarkable electrochemical performance based on polyaniline-polyacrylamide/sodium alginate hydrogels

The electrochemical performance of polyaniline-based all-gel-state supercapacitor (AGSSC) is significantly depended on the dispersity and mass loaded of polyaniline (PANI). In this manuscript, inspired by the properties of surfactant, sodium dodecylbenzene sulfonate (SDBS) was introduced to prepare various PANI-polyacrylamide/sodium alginate/SDBS (PANIy-PSSx) AGSSCs. With presence of SDBS, the electrochemical performance of PANIy-PSSx AGSSCs was greatly improved, displaying a trend of initial rise and then decrease with increasing concentration of SDBS from 0 to 0.75 wt%. As the content of SDBS was 0.5 wt%, the resulting PANI1.0-PSS0.5 AGSSC displayed the optimum electrochemical properties with area capacitance and energy density of 913.79 mF/cm2 and 81.23 μWh/cm2, respectively. The capacitance rate of PANI1.0-PSS0.5 AGSSC was still more than 93 % after 2000 cycles of sequential CV scans at the scan rate of 200 mV/s. These data were greatly higher than many reported PANI-based AGSSCs. Moreover, the resultant PANI1.0-PSS0.5 AGSSC could maintain high electrochemical performance even after various operations, such as compression, puncture, fluctuating temperature, bending situations and various voltage windows and series-parallel connections. The resultant PANI1.0-PSS0.5 AGSSC had the wide potentials to satisfy the real application requirements. This study offered a facile strategy for design and preparation of flexible supercapacitor with excellent electrochemical performance.

Dual-Purpose CuFe2O4-rGO-Based Nanocomposite for Asymmetric Flexible Supercapacitors and Catalytic Reduction of Nitroaromatic Derivatives

Energy storage and environmental pollution are two major global concerns in today's scenario. As a result of the momentous exhaustion of fossil fuels, the generation of energy from renewable sources is gaining immense importance. However, the irregular availability of energy from these renewable sources is the major encounter to achieve sustainable energy harvesting technology, yielding efficient but continuous and reliable energy supplies. Apart from the requirement of state-of-the-art heavy-duty technologies such as transportation, defense, etc., in the modern lifestyle to fulfill the demand for flexible electronic devices, the development of high-performance mechanically flexible all-solid-state supercapacitors is increasing massively. On the other hand, to cater to the need for accessibility of clean water for healthy lives, several technologies are evolving to treat wastewater and groundwater. Hence, the development of efficient catalysts for destroying water pollutants is an attractive approach. Considering these two crucial facets, in this paper, we have demonstrated the multifunctional features of a CuFe2O4-rGO nanocomposite, which was exploited to fabricate a high-performance mechanically flexible all-solid-state asymmetric supercapacitor and simultaneously used as an efficient but easily recoverable catalyst for the transformation of different nitroaromatic compounds. We have also demonstrated the conversion of trifluralin (a herbicide), which is present in the water body as a pollutant, to its corresponding amine derivatives, which can be utilized in the preparation of important pharmaceutical products.