An Edible Rechargeable Battery.

Edible electronics is a growing field that aims to produce digestible devices using only food ingredients and additives, thus addressing many of the shortcomings of ingestible electronic devices. Edible electronic devices will have major implications for gastrointestinal tract monitoring, therapeutics, as well as rapid food quality monitoring. Recent research has demonstrated the feasibility of edible circuits and sensors, but to realize fully edible electronic devices edible power sources are required, of which there have been very few examples. Drawing inspiration from living organisms, which use redox cofactors to power biochemical machines, a rechargeable edible battery formed from materials eaten in everyday life is developed. The battery is realized by immobilizing riboflavin and quercetin, common food ingredients and dietary supplements, on activated carbon, a widespread food additive. Riboflavin is used as the anode, while quercetin is used as the cathode. By encapsulating the electrodes in beeswax, a fully edible battery is fabricated capable of supplying power to small electronic devices. The proof-of-concept battery cell operated at 0.65 V, sustaining a current of 48 µA for 12 min. The presented proof-of-concept will open the doors to new edible electronic applications, enabling safer and easier medical diagnostics, treatments, and unexplored ways to monitor food quality.

Self-Powered Edible Defrosting Sensor.

Improper freezing of food causes food waste and negatively impacts the environment. In this work, we propose a device that can detect defrosting events by coupling a temperature-activated galvanic cell with an ionochromic cell, which is activated by the release of ions during current flow. Both the components of the sensor are fabricated through simple and low-energy-consuming procedures from edible materials. The galvanic cell operates with an aqueous electrolyte solution, producing current only at temperatures above the freezing point of the solution. The ionochromic cell exploits the current generated during the defrosting to release tin ions, which form complexes with natural dyes, causing the color change. Therefore, this sensor provides information about defrosting events. The temperature at which the sensor reacts can be tuned between 0 and -50 °C. The device can thus be flexibly used in the supply chain: as a sensor, it can measure the length of exposure to above-the-threshold temperatures, while as a detector, it can provide a signal that there was exposure to above-the-threshold temperatures. Such a device can ensure that frozen food is handled correctly and is safe for consumption. As a sensor, it could be used by the workers in the supply chain, while as a detector, it could be useful for end consumers, ensuring that the food was properly frozen during the whole supply chain.

Caffeine-Derived Noble Carbons as Ball Milling-Resistant Cathode Materials for Lithium-Ion Capacitors.

Energy consumption is a growing phenomenon in our society causing many negative effects such as global warming. There is a need for the development of new sustainable materials for energy storage. Carbons are materials derivable from biowaste that can rather easily store energy due to their high conductivity and surface area. However, their large-scale processing is challenging as derived materials can be rather heterogeneous and homogenization requires ball milling, a process that can damage carbons in the process of oxidation. Herein, we have prepared caffeine-derived noble nitrogen-doped carbon that withstands the ball milling process without significant oxidation. Additionally, it performs extraordinarily as a cathode material for lithium-ion capacitors, making it an attractive biowaste-derived alternative to commercial heavy metal cathodes.

The Functional Chameleon of Materials Chemistry-Combining Carbon Structures into All-Carbon Hybrid Nanomaterials with Intrinsic Porosity to Overcome the "Functionality-Conductivity-Dilemma" in Electrochemical Energy Storage and Electrocatalysis.

Nanoporous carbon materials can cover a remarkably wide range of physicochemical properties. They are widely applied in electrochemical energy storage and electrocatalysis. As a matter of fact, all these applications combine a chemical process at the electrode-electrolyte interface with the transport (and possibly the transfer) of electrons. This leads to multiple requirements which can hardly be fulfilled by one and the same material. This "functionality-conductivity-dilemma" can be minimized when multiple carbon-based compounds are combined into porous all-carbon hybrid nanomaterials. This article is giving a broad and general perspective on this approach from the viewpoint of materials chemists. The problem and existing solutions are first summarized. This is followed by an overview of the most important design principles for such porous materials, a chapter discussing recent examples from different fields where the formation of comparable structures has already been successfully applied, and an outlook over the future development of this field that is foreseen.

Oxygen-rich poly-bisvanillonitrile embedded amorphous zirconium oxide nanoparticles as reusable and porous adsorbent for removal of arsenic species from water.

A new oxygen-rich porous polymer based on bisvanillonitrile was synthesized and characterized. This polymer was employed as support for the anchoring of 14.5 w% amorphous zirconium oxide nanoparticles. The formation of homogeneously dispersed nanoparticles in the poly-bisvanillonitrile (PBVN) host material was confirmed using N2-sorption, XRPD, XPS and electron microscopy. The combination of zirconium oxide nanoparticles having active adsorption sites with the porous supporting material showed excellent adsorption of arsenic species. The resulting adsorption capacities of the hybrid material extend to 245 mg g-1 for arsenite (AsIII) and 115 mg g-1 for arsenate (AsV). Moreover, adsorption kinetics showed a fast removal of both arsenic species with initial adsorption rate h of 0.0646 mg g-1 min-1 for arsenite and 0.0746 mg g-1 min-1 for arsenate. The immobilization was not interfered by the presence of other compounds in solution, indicating the applicability in real working environments. The material could be regenerated in a continuous mode using a 0.1 mol L-1 sodium hydroxide solution at 70 °C to desorb arsenic.

Schiff-bases for sustainable battery and supercapacitor electrodes.

The quest for more efficient ways to store electrical energy prompted the development of different storage devices over the last decades. This includes but is not limited to different battery concepts and supercapacitors. However, modern batteries rely on electrochemical principles that often involve transition metals which can for instance suffer from toxicity or limited availability. More sustainable alternatives are needed. This sparked the search for organic electrode materials. Nevertheless, compared to their inorganic counterparts, organic electrode materials remain less intensely investigated. Besides the often more complicated electrochemical principles, one likely reason for that are the complex synthetic skills required to develop novel organic materials. Here we review materials synthesized by an old and comparably simple reaction from the field of organic chemistry, namely Schiff-base formation. This reaction can often yield materials under relatively mild conditions, making them especially interesting for the formation of sustainable electrodes. The main weakness of Schiff-base materials, susceptibility to hydrolysis, is of limited concern in most of the battery systems as they mostly anyways require water-free conditions. This review gives an overview of some selected nanomaterials obtained from Schiff-base formation as well as their carbonized derivatives which are of interest for energy storage. Firstly, the general chemistry of Schiff-bases is introduced, followed by an in-depth survey of the most important breakthroughs in the formation of organic battery electrodes that involve materials based on Schiff-base reaction. Lastly, an outlook considering the main hurdles as well as future perspectives of this research area is given.

Interplay of Porosity, Wettability, and Redox Activity as Determining Factors for Lithium-Organic Electrochemical Energy Storage Using Biomolecules.

Although several recent publications describe cathodes for electrochemical energy storage materials made from regrown biomass in aqueous electrolytes, their transfer to lithium-organic batteries is challenging. To gain a deeper understanding, we investigate the influences on charge storage in model systems based on biomass-derived, redox-active compounds and comparable structures. Hybrid materials from these model polymers and porous carbon are compared to determine precisely the causes of exceptional capacity in lithium-organic systems. Besides redox activity, particularly, wettability influences capacity of the composites greatly. Furthermore, in addition to biomass-derived molecules with catechol functionalities, which are described commonly as redox-active species in lithium-bio-organic systems, we further describe guaiacol groups as a promising alternative for the first time and compare the performance of the respective compounds.

Vanillin decorated chitosan as electrode material for sustainable energy storage.

Energy storage materials made from bioresources are crucial to fulfil the need for truly sustainable energy storage. In this work, vanillin, being a lignin-derived molecule, is coupled to chitosan, a biobased polymer backbone, and used as a redox active electrode material. The structure of those electrodes is highly defined, leading to better product security than in lignin based electrodes, which have been presented as sustainable electrodes in the past. With over 60% of saccharide units in chitosan functionalised by vanillin, the concentration of redox functionalities in the copolymer is significantly higher than in lignin materials. Composites with carbon black require no further binders or additives to be used as electrode material and show reversible charge storage up to 80 mA h g-1 (respective to the total electrode material) and good stability. Consequently, these electrodes are amongst the best performing electrodes made from regrown organic matter.