Direct solar energy conversion on zinc-air battery.

A concept of solar energy convertible zinc-air battery (SZAB) is demonstrated through rational design of an electrode coupled with multifunction. The multifunctional electrode is fabricated using nitrogen-substituted graphdiyne (N-GDY) with large π-conjugated carbonous network, which can work as photoresponsive bifunctional electrocatalyst, enabling a sunlight-promoted process through efficient injection of photoelectrons into the conduction band of N-GDY. SZAB enables direct conversion and storage of solar energy during the charging process. Such a battery exhibits a lowered charge voltage under illumination, corresponding to a high energy efficiency of 90.4% and electric energy saving of 30.3%. The battery can display a power conversion efficiency as high as 1.02%. Density functional theory calculations reveal that the photopromoted oxygen evolution reaction kinetics originates from the transition from the alkyne bonds to double bonds caused by the transfer of excited electrons, which changes the position of highest occupied molecular orbital and lowest unoccupied molecular orbital, thus greatly promoting the formation of intermediates to the conversion process. Our findings provide conceptual and experimental confirmation that batteries are charged directly from solar energy without the external solar cells, providing a way to manufacture future energy devices.

Co(III)-Catalyzed C6-Selective C-H Activation/Pyridine Migration of 2-Pyridones with Propiolates.

A versatile Co(III)-catalyzed C6-selective C-H activation/pyridine migration of 2-pyridones with available propiolates as coupling partners was demonstrated. This method features high atom economy, excellent regioselectivity, and good functional group tolerance by employing an inexpensive Co(III) catalyst under mild reaction conditions. Moreover, gram-scale synthesis and late-stage modifications of pharmaceuticals were performed to prove the effectiveness of these synthetic approaches.

Advanced Multilayered Electrode with Planar Building Blocks Structure for High-Performance Lithium-Ion Storage.

To achieve the high-performance of lithium-ion battery, the optimization of electrode materials has generally been considered as the one of the important methods. But most of those works pay attention to the new materials preparation or interface modification rather than the structural innovation. Here, an advanced electrode (GDY/BP/GDY-E) with multilevel layered architecture constructed by planar building blocks stacking structure has been designed and fabricated to explore the structure design of the electrode. This new structure is assembled by graphdiyne (GDY) and black phosphorus (BP) in parallel to form a building block (GDY/BP/GDY). The electric fields between the two GDY sides of the planar building block structure contribute to the superior migration dynamics of lithium ions and desirable pseudocapacitance behavior. Meanwhile, the planar stacking structure of GDY/BP/GDY can efficiently inhibit volume expansion of BP and a series of parasitic reactions of electrolytes during the long-term cycling. The advanced GDY/BP/GDY-E exhibits excellent high-rate performance (1418.8 mAh g-1 at 0.1 A g-1 ) and cycling stability (391.7 mAh g-1 after 5000 cycles at 10 A g-1 ). Such structural design of electrode materials shows a new way to develop high-performance electrodes.

Boosting Fe Cationic Vacancies with Graphdiyne to Enhance Exceptional Pseudocapacitive Lithium Intercalation.

Modulating the electronic structure of electrode materials at atomic level is the key to controlling electrodes with outstanding rate capability. On the basis of modulating the iron cationic vacancies (IV) and electronic structure of materials, we proposed the method of preparing graphdiyne/ferroferric oxide heterostructure (IV-GDY-FO) as anode materials. The goal is to motivate lithium-ion batteries (LIBs) toward ultra-high capacity, superior cyclic stability, and excellent rate performance. The graphdiyne is used as carriers to disperse Fe3 O4 uniformly without agglomeration and induce high valence of Fe with reducing the energy in the system. The presence of Fe vacancy could regulate the charge distribution around vacancies and adjacent atoms, leading to facilitate electronic transportation, enlarge the lithium-ion diffusion, and decrease Li+ diffusion barriers, and thus displaying significant pseudocapacitive process and advantageous lithium-ion storage. The optimized electrode IV-GDY-FO reveals a capacity of 2084.1 mAh g-1 at 0.1 C, superior cycle stability and rate performance with a high specific capacity of 1057.4 mAh g-1 even at 10 C.

Directly Growing Graphdiyne Nanoarray Cathode to Integrate an Intelligent Solid Mg-Moisture Battery.

A continuous humidity and solar-light dual responsive intelligent solid Mg-moisture battery (SMB) with a graphdiyne nanosheets array was fabricated. The integrated battery works based on a new concept of chemical bond conversion on the surface of the graphdiyne nanosheets array that is grown in situ on a 3D melamine sponge (GDY/MS). The unique structure, excellent catalytic, and semiconductor performance of GDY endows the GDY/MS with some outstanding characteristics on trapping and transferring water molecules, catalyzing HER, and utilizing solar energy, making the GDY/MS a new generation cathode for a high-performance intelligent SMB. The performance of the GDY/MS-based smart SMB (GSMB) can be continuously tuned by humidity and solar-light. The GSMB shows a significant positive correlation between open circuit potential (OCP) and humidity, while the natural band gap of GDY makes it further act as a photoelectrode to capture light and generate photoelectrons. The GSMB can be applied as a self-power humidity monitor with an ultrafast response time of <0.24 s, a recovery time of <0.16 s, and a sensitive (36,600%) respiratory sensing performance. This simple and efficient battery-made strategy represents the future development direction of self-power supply equipment, intelligent electronic devices, and intelligent battery integration.

HPO42- enhanced catalytic activity of N, S, B, and O-codoped carbon nanosphere-armored Co9S8 nanoparticles for organic pollutants degradation via peroxymonosulfate activation: critical roles of superoxide radical, singlet oxygen and electron transfer.

In this study, we report a facile synthesis of a novel N, S, B, and O-codoped carbon nanosphere-armored Co9S8 nanoparticle composite (Co9S8@NSBOC) and its superior activation performance toward peroxymonosulfate (PMS) for methylene blue (MB) and ofloxacin degradation. The effects of various experimental parameters and the general applicability of the catalyst were investigated. Particularly, Co9S8@NSBOC exhibited high catalytic activity in a wide pH range of 3-12 and HPO42- exhibited a synergic catalytic effect with Co9S8@NSBOC in the degradation system. Radical quenching tests, EPR measurements and electrochemical analysis demonstrated that the degradation mechanism of pollutants in the Co9S8@NSBOC/PMS system included both radical and non-radical pathways, in which ˙O2-, 1O2 and electron transfer played dominant roles. Co2+, S2-, carbon defects, C[double bond, length as m-dash]O/C-O-C, pyridinic-N, graphitic-N, BC2O and C-S-C species on Co9S8@NSBOC, all contributed to PMS activation. The degradation pathways of MB and ofloxacin were proposed based on HPLC-MS/MS analysis of their degradation intermediates. This work not only presents a facile and practical synthetic method of cobalt sulfide-coupled multi-heteroatom-doped carbocatalysts, but also provides useful insights into their active sites and activation mechanisms toward PMS activation.

Co nanoparticle-embedded N,O-codoped porous carbon nanospheres as an efficient peroxymonosulfate activator: singlet oxygen dominated catalytic degradation of organic pollutants.

In this study, Co nanoparticle-embedded N,O-codoped porous carbon nanospheres (C@Co) with abundant N and O doping, high graphitization, large specific surface area (319 m2 g-1) and a well-developed mesoporous structure were synthesized and characterized thoroughly, and were applied to activate peroxymonosulfate (PMS) for the degradation of methylene blue (MB). Various influential factors affecting the catalytic performance including C@Co dosage, PMS dosage, MB concentration, initial pH, temperature, and co-existing common anions and humic acid (HA) on the MB degradation were systematically investigated. The increase of the C@Co dosage (15-60 mg), PMS dosage (25-100 mg) and reaction temperature (278-308 K) promoted the MB degradation in the C@Co/PMS system. The best performance of the C@Co/PMS system was observed under weakly acidic or nearly neutral conditions. Both the MB concentration (25-100 mg L-1) and Cl- (5-100 mM), NO3- (10-500 mM), CO32- (10-300 mM), HCO3- (1-30 mM) and HA (2-40 mg L-1) had an inhibitory effect on MB degradation, and the degree of decrease in MB degradation increased as their concentrations were enhanced. Interestingly, HPO42- (1-100 mM) had an overall inhibitory effect on the degradation process of MB; however, in comparison with lower concentrations (1-10 mM), an attenuation of the inhibitory effect at higher concentrations (50-100 mM) could be observed. Moreover, the C@Co/PMS system also exhibited general applicability in eliminating various organic pollutants from water such as methyl orange, malachite green, safranine T, Congo red, Rhodamine B, ofloxacin and tetracycline. Classical radical-quenching tests and EPR measurements showed that both the non-radical pathway (major route, involving 1O2) and radical pathway (minor route, involving ˙OH, ˙SO4- and ˙O2-) contribute to the MB degradation. DFT calculations disclosed that the combination of Co-C interactions with graphitic N doping brought in catalytically active sites in C@Co where the charge states of some C atoms were significantly increased. The degradation intermediates of MB during the catalytic reaction were also identified by HPLC-MS and the possible degradation pathway was proposed. Overall, the resultant C@Co can be developed as a novel and efficient heterogeneous catalyst for activating PMS to degrade organic pollutants, and has potential application in environmental remediation.

Humidity and Pressure Dual-Responsive Metal-Water Batteries Enabled by Three-In-One All-Polymer Cathodes for Smart Self-Powered Systems.

A conceptually new class of humidity and pressure dual-responsive smart metal-water batteries (SMWBs) is presented, which displays self-tunable energy release and intriguing perceptibility of human respiration and environmental pressure. This battery is enabled by the direct contact of a metal (e.g., Mg or Zn) anode and a well-designed all-polymer dual-sensitive moisture electrode (DSME) made from semiconductive polymer (e.g., polypyrrole)-wrapped 3D macroporous polyurethane sponge, without additional electrolytes and separator. A DSME is cost-effective, easily scalable, compressible, and able to act as a moisture carrier, a hydrogen evolution catalyst, and a pressure and humidity dual-sensitive unit simultaneously. Unique three-in-one integration in the DSME enables favorable modulation of electron/mass transport or redox reactions in the SMWB upon different stimulations. Thus, the assembled SMWB not only delivers good discharge performance with smart energy management but also serves as a reliable self-powered bifunctional responsor for the real-time monitoring of respiration and the perceptibility of pressure. Based on various active metal-polymer pairs (Mg/Zn vs polypyrrole/polyaniline), we also developed a series of dual-responsive batteries, demonstrating a general design idea.

Tactile UV- and Solar-Light Multi-Sensing Rechargeable Batteries with Smart Self-Conditioned Charge and Discharge.

A tactile, UV- and solar-light multi-sensing smart rechargeable Zn-air battery (SRZAB) with excellent cell performance, self-conditioned charge/discharge, and reliable environmental responsivity is made by using multi-scale conjugated block-copolymer-carbon nanotube-polyurethane foam assemblies as both a self-standing air electrode and a sensing unit. Multiscale engineering fully exploits the multi-synergy among components to endow the newly designed metal-free multi-sensing air electrode (MSAE) with bifunctional oxygen reduction and evolution activities, pressure sensitivity, and photothermal and photoelectric conversion functions in a single electrode, enabling effective regulation of interface properties, electronic/ionic transport, or redox reactions in SRZAB upon various stimulations and establishing multiple working principles. MSAE-driven SRZAB can be used as compressible power sources, self-powered pressure and optical sensors and light-to-electrochemical energy systems.