High‐Performance Solution‐Processed Double‐Walled Carbon Nanotube Transparent Electrode for Perovskite Solar Cells

Double‐walled carbon nanotubes are between single‐walled carbon nanotubes and multiwalled carbon nanotubes. They are comparable to single‐walled carbon nanotubes with respect to the light optical density, but their mechanical stability and solubility are higher. Exploiting such advantages, solution‐processed transparent electrodes are demonstrated using double‐walled carbon nanotubes and their application to perovskite solar cells is also demonstrated. Perovskite solar cells which harvest clean solar power have attracted a lot of attention as a next‐generation renewable energy source. However, their eco‐friendliness, cost, and flexibility are limited by the use of transparent oxide conductors, which are inflexible, difficult to fabricate, and made up of expensive rare metals. Solution‐processed double‐walled carbon nanotubes can replace conventional transparent electrodes to resolve such issues. Perovskite solar cells using the double‐walled carbon nanotube transparent electrodes produce an operating power conversion efficiency of 17.2% without hysteresis. As the first solution‐processed electrode‐based perovskite solar cells, this work will pave the pathway to the large‐size, low‐cost, and eco‐friendly solar devices.     

Exploration of Advanced Electrode Materials for Rechargeable Sodium‐Ion Batteries

As the rapid growth of the lithium‐ion battery (LIB) market raises concerns about limited lithium resources, rechargeable sodium‐ion batteries (SIBs) are attracting growing attention in the field of electrical energy storage due to the large abundance of sodium. Compared with the well‐developed commercial LIBs, all components of the SIB system, such as the electrode, electrolyte, binder, and separator, need further exploration before reaching a practical industrial application level. Drawing lessons from the LIB research, the SIB electrode materials are being extensively investigated, resulting in tremendous progress in recent years. In this article, the progress of the research on the development of electrode materials for SIBs is summarized. A variety of new electrode materials for SIBs, including transition‐metal oxides with a layered or tunnel structure, polyanionic compounds, and organic molecules, have been proposed and systematically investigated. Several promising materials with moderate energy density and ultra‐long cycling performance are demonstrated. Appropriate doping and/or surface treatment methodologies are developed to effectively promote the electrochemical properties. The challenges of and opportunities for exploiting satisfactory SIB electrode materials for practical applications are outlined.     

Thick Electrode Batteries: Principles,Opportunities, and Challenges

The ever‐growing portable electronics and electric vehicle markets heavily influence the technological revolution of lithium batteries (LBs) toward higher energy densities for longer standby times or driving range. Thick electrode designs can substantially improve the electrode active material loading by minimizing the inactive component ratio at the device level, providing a great platform for enhancing the overall energy density of LBs. However, extensive efforts are still needed to address the challenges that accompany the increase in electrode thickness, not limited to sluggish charge kinetics and electrode mechanical instability. In this review, the principles and the recent developments in the fabrication of thick electrodes that focus on low‐tortuosity structural designs for rapid charge transport and integrated cell configuration for improved energy density, cell stability, and durability are summarized. Advanced thick electrode designs for application in emerging battery chemistries such as lithium metal electrodes, solid state electrolytes, and lithium–air batteries are also discussed with a perspective on their future opportunities and challenges. Finally, suggestions on the future directions of thick electrode battery development and research are suggested.     

Role of mediators in electron transport from glucose oxidase redox centre to electrode surface in a covalently coupled enzyme paste electrode

We have studied the glucose oxidase immobilized carbon paste electrodes in the presence and absence of small mediator molecules. We have used p-benzoquinone and riboflavin as mediators in our studies. The effect of mediator molecules on the electron transfer between the enzyme redox centre and the electrode surface was explained from the cyclic voltammograms and rotating disk electrode data. In the absence of oxygen, we have noted that the mediators play a central role in the electron transfer. We have also proposed a possible mechanism for the electron transfer from enzyme active site to the electrode surface via mediators, based on our observations. Dedicated to the memory of Professor J Das     

Cell-Membrane Inspired Multifunctional Nanocoating for Rescuing the Active-Material Microenvironment in High-Capacity Sulfur Cathode

Achieving healthy active-material microenvironment (ME@AM) for stable and efficient electron/ion transport around each active-material particle is crucial for high-performance battery electrodes. However, this goal has been proved extremely challenging for most high-capacity AMs such as sulfur, owing to its notable volume change and severe shuttle effect. Here, a multifunctional hybrid material with zein protein reinforced catalytic single Cu atom/carbon composite (Cu─C) (zein/Cu─C) is coated onto sulfur/carbon (SC) particle, to prepare the advanced zein/Cu─C@SC core–shell particle. Similar to the multifunctional cell membrane well-known in biology, this multifunctional zein/Cu─C coating helps build a healthy and stable ME@AM within sulfur cathode. Specifically, it can simultaneously provide robust protective shell for the AM particle, adsorption and catalyst function to the dissolved polysulfides, and AM surface treatment to improve AM/conductive agent interface. All these functions are the keys to build and maintain a healthy ME@AM in sulfur cathode. This study not only brings effective solutions to the challenges in volume-change high-capacity sulfur active materials and beyond, but also helps achieve comprehensive understanding of the key factors controlling the structuring and final quality of ME@AM.     

Recent developments and applications of immobilized laccase

Laccase is a promising biocatalyst with many possible applications, including bioremediation, chemical synthesis, biobleaching of paper pulp, biosensing, textile finishing and wine stabilization. The immobilization of enzymes offers several improvements for enzyme applications because the storage and operational stabilities are frequently enhanced. Moreover, the reusability of immobilized enzymes represents a great advantage compared with free enzymes. In this work, we discuss the different methodologies of enzyme immobilization that have been reported for laccases, such as adsorption, entrapment, encapsulation, covalent binding and self-immobilization. The applications of laccase immobilized by the aforementioned methodologies are presented, paying special attention to recent approaches regarding environmental applications and electrobiochemistry.     

Lyophilized 3D Lithium Vanadium Phosphate/Reduced Graphene Oxide Electrodes for Super Stable Lithium Ion Batteries

3D lithium vanadium phosphate/reduced graphene oxide porous structures are prepared using a facile lyophilization process. The 3D porous nature of these lyophilized electrodes along with their high surface area lead to high rate capability and specific capacity. A high specific discharge capacity of ≈192 mAh g^?1 is observed at 0.5 C. The cycling performance is noteworthy, as these lyophilized samples at 0.5 and 1 C do not show any fading, even after 1000 and 5000 cycles, respectively. Capacity retention of ≈96.2% is observed at the end of 10 000 cycles at 20 C. This remarkable cycling performance is attributed to the structural stability of the 3D porous network and is confirmed using scanning electron microscopy and selected area electron diffraction after 10 000 cycles of consecutive charging and discharging at 20 C.