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In the dynamic landscape of the Internet of Things (IoT), where smart devices are reshaping our world, nanomaterials can play a pivotal role in ensuring the IoT's sustainability. These materials are poised to redefine the development of smart devices, not only enabling cost-effective fabrication but also unlocking novel functionalities. As the IoT is set to encompass an astounding number of interconnected devices, the demand for environmentally friendly nanomaterials takes center stage. This Focus Issue spotlights cutting-edge research that explores the intersection of nanomaterials and sustainability. The collection delves deep into this critical nexus, encompassing a wide range of topics, from fundamental properties to applications in devices (e.g. sensors, optoelectronic synapses, energy harvesters, memory components, energy storage devices, and batteries), aspects concerning circularity and green synthesis, and an array of materials comprising organic semiconductors, perovskites, quantum dots, nanocellulose, graphene, and two-dimensional semiconductors. Authors not only showcase advancements but also delve into the sustainability profile of these materials, fostering a responsible endeavour toward a green IoT future. [ABSTRACT FROM AUTHOR]

Developing sustainable and affordable anode materials that are capable of delivering high performance in both lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs) remains a significant challenge. Bimetallic selenide@carbon hybrids are considered as one of the most promising anode materials in LIBs and SIBs due to their high electronic conductivity, high specific capacity, and fast reaction kinetics. Herein, a series of bimetallic selenide@carbon hybrid nanotubes are successfully prepared as anodes of LIBs or SIBs based on the dual regulation of component and micro‐nanostructure. The selenization strategy plays a key important role in determining the composition, microstructure, and electrochemical energy storage properties of anode materials. As a consequence, the ZnSe/CoSe2@NPC NTs(I)‐600 exhibit a reversible capacity of 1328.3 mAh g−1 at 0.1 A g−1 and superior rate capability (269.1 mAh g−1 at 10 A g−1) towards Li+ storage. Meanwhile, ZnSe/CoSe2@NPC NTs(II)‐700 achieve 354.1 mAh g−1 at 0.1 A g−1 and ultralong cycling stability (97.6% of capacity retention after 40 000 cycles at 10 A g−1) used as anode materials in SIBs. This study provides a feasible strategy to fabricate selenide‐based composites as anode materials for high‐performance LIBs and SIBs via architecture engineering and composition tailoring. [ABSTRACT FROM AUTHOR]

High-performance electrocatalysts are critical to support emerging electrochemical energy storage and conversion technologies. Graphite-derived materials, including fullerenes, carbon nanotubes, and graphene, have been recognized as promising electrocatalysts and electrocatalyst supports for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and carbon dioxide reduction reaction (CO2RR). Effective modification/functionalization of graphite-derived materials can promote higher electrocatalytic activity, stability, and durability. In this review, the mechanisms and evaluation parameters for the above-outlined electrochemical reactions are introduced first. Then, we emphasize the preparation methods for graphite-derived materials and modification strategies. We further highlight the importance of the structural changes of modified graphite-derived materials on electrocatalytic activity and stability. Finally, future directions and perspectives towards new and better graphite-derived materials are presented. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (SIBs) are gaining renewed interest as a promising alternative to the already commercialized lithium‐ion batteries. The large abundance, low cost, and similar electrochemistry of sodium (compared with lithium) is attracting the attention of the research community for their deployment in energy storage devices. Despite the fact that there are adequate cathode materials, the choice of suitable anodes for SIBs is limited. Graphite, the most versatile anode for LIBs, exhibits poor performance in case of SIBs. Amorphous or disordered carbons (hard and soft carbon) have been the most promising and cost‐effective anode materials for SIBs. This Review discusses the recent advances of various forms of amorphous or disordered carbons used in SIBs with emphasis on their synthesis processes and relationship between microstructure, morphology, and performance. A profound understanding of the charge storage mechanisms of sodium in these carbon materials has been deliberated. The performance of these anode materials also depends upon electrolyte optimization, which has been aptly conferred. However, these anodes are often plagued with large voltage loss, low initial coulombic efficiency, and formation of solid electrolyte interphase. In order to overcome these challenges, several mitigation strategies have been put forward in a concise way to offer visions for the deployment of these amorphous carbon materials for the progress and commercial success of SIBs. [ABSTRACT FROM AUTHOR]

Electrochemical energy conversion and storage play crucial roles in meeting the increasing demand for renewable, portable, and affordable power supplies for society. The rapid development of nanostructured materials provides an alternative route by virtue of their unique and promising effects emerging at nanoscale. In addition to finding advanced materials, structure design and engineering of electrodes improves the electrochemical performance and the resultant commercial competitivity. Regarding the structural engineering, controlling the geometrical parameters (i.e., size, shape, hetero‐architecture, and spatial arrangement) of nanostructures and thus forming well‐defined nanostructure (WDN) electrodes have been the central aspects of investigations and practical applications. This review discusses the fundamental aspects and concept of WDNs for energy conversion and storage, with a strong emphasis on illuminating the relationship between the structural characteristics and the resultant electrochemical superiorities. Key strategies for actualizing well‐defined features in nanostructures are summarized. Electrocatalysis and photoelectrocatalysis (for energy conversion) as well as metal‐ion batteries and supercapacitors (for energy storage) are selected to illustrate the superiorities of WDNs in electrochemical reactions and charge carrier transportation. Finally, conclusions and perspectives regarding future research, development, and applications of WDNs are discussed. [ABSTRACT FROM AUTHOR]

The increasing development of wearable, portable, implantable, and highly integrated electronic devices has led to an increasing demand for miniaturization of energy storage devices. In recent years, supercapacitors, as an energy storage device, have received enormous attention owing to their excellent properties of quick charge and discharge, high power density, and long life cycle with minimal maintenance. Micro‐supercapacitors (MSCs) as a promising candidate for miniaturized energy storage components have undergone considerable theoretical and experimental investigations. Particularly, planar MSCs with a 2D architecture design have more attractive application prospects due to their flexible design and excellent electrochemical performance. However, the major drawbacks of MSCs are their intrinsically low energy density. For this reason, researchers have conducted much investigation to improve their energy density in order to promote their practical application. Herein, the recent development and progress of planar MSCs from the scope of the substrates, electrode materials, fabrication methods, electrochemical properties, and applications are discussed. Finally, the currently existing challenges and developments associated with planar MSCs are also discussed. All in all, planar MSCs have great application potential in various fields of electrochemical energy storage, self‐powered wireless sensors, and stimuli‐responsive and photoresponsive, alternating current line filtering. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (SIBs) have emerged as one of the most promising and competitive energy storage systems due to abundant sodium resources and its environmentally friendly features. However, further improvements in the engineering of the SIB electrode/electrolyte interphase—which directly determines the Na‐ion transfer behavior, material structure stability, and sodiation/desodiation property—are highly recommended to meet the continuously increasing requirements for secondary power sources. Reasonably speaking, to promote SIBs, the advanced and controllable interphase/electrode engineering approach exhibits promise by rationally designing the bulk electrode and generating a well‐defined interphase. Atomic layer deposition (ALD) technology, with atomic‐scale deposition, superior uniformity, excellent conformality, and a self‐limiting nature, is thus expected to address the current challenges facing SIBs in terms of low energy density, limited cycling life, and structural instability, and to promote innovations such as multifunctional electrodes and nanostructured materials for advanced SIBs. This review summarizes and discusses the most recent advancements in the interphase engineering of SIBs by ALD via modifying traditional electrodes and designing advanced electrodes (such as 3D, organic, and protected sodium metal electrodes). Furthermore, based on the recent critical progress and current scientific understanding, future perspectives for the engineering of next‐generation SIB electrodes by ALD can be provided. [ABSTRACT FROM AUTHOR]

Electrochemical urea oxidation reaction (UOR) offers a promising alternative to the oxygen evolution reaction (OER) in clean energy conversion and storage systems. Nickel‐based catalysts are regarded as highly promising electrocatalysts for the UOR. However, their effectiveness is significantly hindered by the unavoidable self‐oxidation reaction of nickel species during UOR. To address this challenge, we proposed an interface chemistry modulation strategy to boost UOR kinetics by creating a high‐energy interfacial heterostructure. This heterostructure incorporates Ag at the CoOOH@NiOOH heterojunction interface, where strong interactions significantly promote the electron exchanges at the heterojunction interface between ‐OH and ‐O groups. Consequently, the improved electron delocalization leads to the formation of stronger bonds between Co sites and urea CO(NH2)2, promoting a preference for urea to occupy Co active sites over OH*. The resulting catalyst, Ag−CoOOH@NiOOH, demonstrates ultrahigh UOR activity with a low potential of 1.33 V at 100 mA cm−2. The fabricated catalyst exhibits a mass activity over 11.9 times greater than the initial cobalt oxyhydroxide. The rechargeable urea‐assisted zinc‐air batteries (ZABs) achieve a record‐breaking energy efficiency of 74.56 % at 1 mA cm−2, remarkable durability (1000 hours at a current density of 50 mA cm−2), and quick charge performances. [ABSTRACT FROM AUTHOR]

Biomass-waste activated carbon/molybdenum oxide/molybdenum carbide ternary composites are prepared using a facile in-situ pyrolysis process in argon ambient with varying mass ratios of ammonium molybdate tetrahydrate to porous peanut shell activated carbon (PAC). The formation of MoO2 and Mo2C nanostructures embedded in the porous carbon framework is confirmed by extensive structural characterization and elemental mapping analysis. The best composite when used as electrodes in a symmetric supercapacitor (PAC/MoO2/Mo2C-1//PAC/MoO2/Mo2C-1) exhibited a good cell capacitance of 115 F g−1 with an associated high specific energy of 51.8 W h kg−1, as well as a specific power of 0.9 kW kg−1 at a cell voltage of 1.8 V at 1 A g−1. Increasing the specific current to 20 A g−1 still showcased a device capable of delivering up to 30 W h kg−1 specific energy and 18 kW kg−1 of specific power. Additionally, with a great cycling stability, a 99.8% coulombic efficiency and capacitance retention of ~83% were recorded for over 25,000 galvanostatic charge-discharge cycles at 10 A g−1. The voltage holding test after a 160 h floating time resulted in increase of the specific capacitance from 74.7 to 90 F g−1 at 10 A g−1 for this storage device. The remarkable electrochemical performance is based on the synergistic effect of metal oxide/metal carbide (MoO2/Mo2C) with the interconnected porous carbon. The PAC/MoO2/Mo2C ternary composites highlight promising Mo-based electrode materials suitable for high-performance energy storage. Explicitly, this work also demonstrates a simple and sustainable approach to enhance the electrochemical performance of porous carbon materials. [ABSTRACT FROM AUTHOR]

[Display omitted] Rechargeable zinc (Zn) metal batteries (RZMBs) are demonstrated as sustainable and low-cost alternative in the energy storage industry of the future. However, the elusive Zn deposition behavior and water-originated parasitic reactions bring significant challenges to the fabrication and commercialization of Zn anodes, especially under high plating/stripping capacity. In this work, the ferromagnetic interface in conjunction with the magnetic field (MF) to effectively address these fabrication hurdles is proposed. The introduction of ferromagnetic layer with high chemical durability not only maintains the long-term regulating deposition steadily by magnetic field, but also plays a significant role in preventing side reactions, hence reducing gas production. These merits allow Zn-anode to achieve over 350 h steady Zn-deposition with a depth of discharge (DOD Zn) up to 82% and translates well to ZnFe-MF||V 2 O 5 full cells, supporting stable cycling at high mass loading of 13.1 mg/cm2, which makes RZMBs configurations promising for commercial applications. [ABSTRACT FROM AUTHOR]

Exploring highly efficient nonprecious metal-based single-atom catalysts (SACs) toward the electrocatalytic oxygen reduction reaction (ORR) is critical for the sustainable development of ORR-related energy conversion and storage systems. However, the scalable synthesis, delicate regulation of the coordination environment and molecular-level elucidation of the electrocatalytic mechanism remain challenging. Herein, we report a facile gram-scale synthesis of atomically dispersed Co sites anchored on N-doped carbon nanofibers (noted as Co-SA@N-CNFs) via a reliable predesigned phenolic resin-mediated strategy for efficient oxygen reduction electrocatalysis. The local coordination configuration of the single-atomic Co sites is proposed as the Co-N 4 O moiety with one O atom in the axial direction perpendicular to the Co-N 4 plane. Theoretical calculations uncover that, compared with the common Co-N 4 single sites, the formation of Co-N 4 O configuration is beneficial to reduce the reaction energy barrier, adjust the bond length between the metal sites and the intermediates, and also increase the electric conductivity. Therefore, the Co-SA@N-CNFs demonstrated distinguished ORR activity, outstanding electrochemical stability and methanol tolerance in KOH electrolyte. Furthermore, when assembled in liquid and flexible solid-state rechargeable zinc-air batteries (ZABs), the Co-SA@N-CNFs-equipped ZABs exhibited higher power densities, larger specific capacities and extraordinary cycling performance, compared with the Pt/C-based ZABs. The simple and robust methodology for the mass production of SACs and the engineered coordination environment for performance optimization inspire the future design of a wide range of SACs for energy devices. [Display omitted] • A facile and robust "phenolic resin-bridged" synthesis of single-atom catalysts is developed. • The Co-SA@N-CNFs exhibit excellent ORR activity and high methanol tolerance. • The axial O atom modulates the coordination environment of center Co atoms • The Zn-air battery equipped with Co-SA@N-CNFs shows superior cycling stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • N-doped porous carbons displaying different properties were fluorinated. • The total N content remains unchanged during fluorination. • Fluorination does not decrease drastically the specific surface area. • A huge decomposition in F 2 gas is avoided by the use of mild conditions. Porous carbons are used in various applications for energy storage. Nitrogen doping of these carbons modifies their electrochemical and chemical properties and co-doping them with fluorine atoms, appears as a promising route to further tailor their physical and chemical properties. The present paper focuses on the gas/solid fluorination with molecular fluorine (F 2) of various types of N-doped porous carbons. The consequences of the fluorination on the porosity of these materials were studied as well as their C F bonding type. Mild conditions avoid a huge decomposition in F 2 gas of these materials and a drastic decrease of their specific surface area. Micropores, which are hosting most of the FeNx catalytic sites, are the most affected by fluorination, and a new N1s XPS peak assigned to pyridinic-N---C F has been identified, coinciding with that of the XPS binding energy of N1s in FeNx. However, molecular fluorine did not react directly with nitrogen atoms in these materials, whatever their type since no N F containing volatile products were evolved during the treatment. Finally, a dual C F bonding, characterized by the coexistence of C F bonds with weakened covalence and covalent C F, is evidenced in all fluorinated N-doped porous carbons. [ABSTRACT FROM AUTHOR]