Multi-Strategy Architecture of High-Efficiency Electrocatalysts for Underwater Zn-H2 O2 Batteries with Superior Power Density of 442 mW cm-2.

A facile multistage regulated strategy is reported to synthesize ZnCo-NC based carbon nanotubes including DMEA induced crystallization, Zn ion activation, and magnetic control growth of carbon nanotubes. Uniform Co distribution and the modulation of Zn, and their catalytic properties are carefully investigated by X-ray absorption spectroscopy and X-ray photoelectron spectroscopy. The surface contents of pyridinic N for the oxygen-reduction reaction (ORR) and the surface contents of CoNx and high valence Co for the oxygen-evolution reaction (OER) can be significantly modulated by Zn content in precursors and the sintering temperature. Furthermore, the catalyst also contains high specific surface areas, high porosity, and high electrochemical active surfaces. Therefore, the ZnCo-NC based catalyst exhibits outstanding bifunctional electrocatalytic activities for ORR with a high Eonset (1.02 V) and E1/2 (0.91 V) and OER with low Ej=10 (1.56 V), better than Pt/C and RuO2 . Importantly, the ZnCo-NC based Zn-H2 O2 batteries achieve the superior power density of 442 mW cm-2 , much higher than 238 and 198 mW cm-2 of Zn-air batteries with ZnCo-NC based catalyst and Pt/C respectively. More importantly, the high-power Zn-H2 O2 batteries can work well in underwater conditions while Zn-air batteries are out of work.

Hierarchical Porous N-Doped Carbon Nanosheets Obtained by Organic-Inorganic Bipolymeric Engineering for Improved Lithium-Sulfur Batteries.

A new route for obtaining N-doped carbon nanosheets through an in situ solid-state thermal organic-inorganic polymerization and carbonization method, with glucose and melamine as precursors, due to different temperature intervals for glucose or melamine polymerization, is reported. At a current rate of 0.2 C, as a cathode for a lithium-sulfur cell, the N-doped carbon nanosheet/sulfur hybrid delivers a high capacity of 1313 and 722 mA h g-1 in the 1st and 200th cycles, respectively; these values are over 40 % higher than that of cells with glucose-derived carbon nanosheets.

Large-Scale Ligand-Free Synthesis of Homogeneous Core-Shell Quantum-Dot-Modified Cs4PbBr6 Microcrystals.

An organic ligand-free solution method is developed for preparing homogeneous core-shell quantum-dot (QD)-modified pure Cs4PbBr6 microcrystals on a large scale (∼12 g) at room temperature. The ligand-free Cs4PbBr6 microcrystals show a high green photoluminescence quantum yield of 76% with 360 nm of excitation light, which is attributed to their unique microarchitecture, with several features including quantum confinement of the outer QDs, stability of the inner Cs4PbBr6 microcrystals, improved light trapping, and interfacial recombination. UV-vis-near-IR and photoluminescence analyses provide valued evidence to support the ligand-free Cs4PbBr6 with synergy between the QDs and microcrystals.

In situ green architecture of the 3D FeZn-N-C based electrocatalyst for efficient oxygen reduction.

We prepared a 3D FeZn-N-C based catalyst by green in situ growth of 1D Fe-N-C carbon nanotubes by introducing ferrocyanide ions on the surface of 2D exfoliated MOF-5. The 1D/2D FeZn-N-C based electrocatalyst is conducive to O2 diffusion and ionic/electron transfer, exhibiting an excellent ORR catalytic performance and a peak power density of 294 mW cm-2 for Zn-air batteries.

Single-cell-array biomass-templated architecture of hierarchical porous electrocatalysts for Zn-air and Zn-H2O2 batteries.

Hierarchically macro-meso-microporous ZIF-67/nori-derived electrocatalysts were synthesized by using single-cell-array nori and ZIF-67 as macroporous and microporous templates, and KOH as a meso/micropore-forming reagent. The ZIF-67/nori-800-based Zn-H2O2 battery achieved a high maximum power density, of 476 mW cm-2, and a specific energy density of 964 W h kg-1 at 50 mA cm-2.

In situ potential-regulated architecture of an ultrafine Ru-based electrocatalyst for ultralow overpotential lithium-oxygen batteries.

An in situ electrochemical reduction strategy is proposed to avoid the aggregation of nano-Ru in lithium batteries for the first time. The high-dispersion face-centered cubic (fcc) nano-Ru is successfully synthesized with an average diameter of 2.0 nm, and the as-assembled lithium-oxygen batteries deliver an excellent cycling performance of 185 cycles and an ultralow overpotential of only 0.20 V at 100 mA g-1.

In situ interfacial architecture of lithium vanadate-based cathode for printable lithium batteries.

Most Li3VO4 anodes are obtained by pre-architecture methods in which Li3VO4 anode materials are prepared with more than six key processes including high-temperature annealing and long preparation time. Herein, we propose an in situ post-architecture strategy including Li3VO4-precursor solution (ink) preparation and then annealing at 250°C. The integrated Li3VO4 based electrode not only possesses good electrical conductivity and porous microstructure but also has superior stability because of Cu anchoring and inclusion by in situ catalysis. The integrated electrode demonstrates a high reversible capacity (865 mA h g-1 at 0.2 A g-1) and good cyclability (100% capacity retention after 200 cycles at 1 A g-1). More importantly, the post-architecture electrode has a high energy density of 773.8 Wh kg-1, much higher than reported Li3VO4-based materials, as well as most cathodes. Therefore, the electrode could be used to the printable cathode of low-voltage high-energy-density lithium batteries.

Low-temperature architecture of a cubic-phase CsPbBr3 single crystal for ultrasensitive weak-light photodetectors.

We present the first report of a water-regulated method for obtaining a cubic-phase CsPbBr3 single crystal that could be frozen at low temperature with a CsBr/PbBr2 ratio of 1 : 1. The cubic CsPbBr3 single-crystal photodetector exhibits a superior responsivity of 278 A W-1, an EQE of 6.63 × 104%, and an ultrahigh detectivity of 4.36 × 1013 Jones under low-power 520 nm irradiation at 3 V.

Biphasic Liquid-Liquid Interface Limit Architecture of High-Quality Perovskite Single-Crystal Sheets for UV Photodetection.

Thin organic-inorganic MAPbX3 perovskite single-crystal sheets have become the hotspot of smart photodetectors because of their low number of trap states, high carrier mobility, long diffusion length, and effective light-receiving area. However, MAPbX3 single crystals are so fragile that single-crystal perovskite sheets with a thickness of ≤100 µm are hard to obtain by cutting. Thin single-crystal MAPbX3 sheets were synthesized by the biphasic liquid-liquid interface limit method with dimethicone/DMSO biphasic films and could be obtained with an adjustable thickness of 1-50 µm and improved crystal quality of the perovskite sheets. The thin MAPbX3 single-crystal sheet-based photodetector exhibits a superior responsivity of 0.88 A W-1, an external quantum efficiency of 276.8%, and an ultrahigh detectivity of 2.26 × 1011 Jones under 395 nm irradiation at 3 V. These values are more than 500% as high as those of the bulk-crystal-based photodetector. In particular, the sheet-based photodetector could retain long-time stability after 4200 on-off cycles.

'Nanoreactors' for photocatalytic H2 evolution in oil-water biphase systems.

Optimization of reaction systems plays a key role in preventing the backward reaction of water splitting. 'Nanoreactors' are formed with nanoporous photocatalyst in a facile H(2) production system, hexane-water biphase system. The rate of H(2) evolution could reach 63.37 mmol h(-1) g(-1) in the biphase system (40% higher than that in the single phase system).

Recent Progress in Electrolytes for Zn-Air Batteries.

Zn-air battery is considered as one of the most promising candidates for next-generation batteries for energy storage due to safety, high energy density, and low cost. There are many challenges in electrolytes for developing high-performance rechargeable Zn-air cells as well as electrocatalysts. An electrolyte is the crucial part of the rechargeable Zn-air batteries that determine their capacity, cycling stability, and lifetime. This paper reviews the most recent progress in designing and fabricating electrolytes in aqueous and flexible Zn-air batteries. The discussion on the surface reaction relationships was covered between air-catalyst-electrolyte and electrolyte-zinc reaction mechanism. We highlight the recent developments of three different electrolytes in zinc-air battery: aqueous electrolyte, room temperature ionic liquid, and quasi-solid flexible electrolyte. Furthermore, the general perspective is proposed for designing and fabricating electrolytes to improve the performance and prolong the lifetime of Zn-air batteries.

Electrolyte Technologies for High Performance Sodium-Ion Capacitors.

Bridging the energy gap between batteries and capacitors, while in principle delivering a supercapacitor-like high power density and long lifespan, sodium-ion capacitors (SIC) have been considered promising energy storage devices that could be commercialized in the near future due to the natural abundance of sodium sources and the performance superiority of SIC devices. Therefore, in the past decade, substantial research efforts have been devoted to their structure and property improvements. With regard to the electrochemical performance of an ion capacitor, except for the electrode, the composition and structure of the electrolytes are also of great importance. Thus, in this mini review, we present a brief summary of the electrolytes developed recently for high performance SIC, including aqueous, organic, and ionic liquid based electrolytes. The influence factors such as ionic conductivities, electrolyte concentrations, electrochemical stable windows, as well as the cost and safety issues are discussed. Furthermore, the future perspectives and challenges in the science and engineering of new electrolytes are also considered. We hope that this review may be helpful to the energy storage community regarding the electrolytes of advanced SIC systems.

Ionic-liquid assisted architecture of amorphous nanoporous zinc-rich carbon-based microstars for lithium storage.

Amorphous Zn-rich nitrogen-doped carbon-based microstars are synthesized using an ionic liquid-assisted method and annealing process. The microstars exhibit a high reversible capacity of 756 mA h g-1 and a capacity retention of 98% after 120 cycles at 0.5 A g-1 due to their large surface area, hierarchical nanopores, and uniform distribution of zinc and nitrogen.

Microconcave MAPbBr3 Single Crystal for High-Performance Photodetector.

We present the first report of a new suspension method for obtaining cubic MAPbBr3 single crystal with a concave surface. The cubic MAPbBr3 crystal with microconcavity possesses good crystallinity and carrier lifetime. Excellent photoelectric performance was provided by the concavity-based MAPbBr3 photodetectors because of the good light trapping and shortened carrier pathway. As a result, the concavity-based photodetector exhibits superior responsivity of 62.9 and 5.43 A W-1 and EQE of 1.50 × 104% and 1.30 × 103% under low-power and high-power 520 nm irradiation of 3.67 µW cm-2 and 35.4 mW cm-2 at 3 V, respectively, which are more than 500% higher than those of the plane-based photodetector. In particular, the concavity-based photodetector has an ultrahigh detectivity of 6.5 × 1012 Jones at ultralow power of 3.67 µW cm-2, which is 6.5 times higher than that of the planar device.

Bimolecular-induced hierarchical nanoporous LiTi2(PO4)3/C with superior high-rate and cycling performance.

We employed a facile bimolecular (glucose and DMEA) assisted hydrothermal reaction and a solid-state reaction to obtain carbon-coated hierarchical LiTi2(PO4)3 on a large scale. The nanoporous material exhibits excellent high-rate and cycling performance owing to enhanced electronic conductivity from the ultrathin carbon layer, Ti3+ and the shortened path for Li+ diffusion by nanoporous frameworks.

Lithium cell-assisted low-overpotential Li-O2 batteries by in situ discharge activation.

We report a novel and facile route to improve the catalytic performance of carbon paper-based electrocatalysts, which can be activated by in situ discharging with the assistance of a Li cell. Our results show that the OER potentials were successfully reduced to ∼3.5 V, much lower than the value of 4.5 V for graphite paper, which is the best result recorded amongst the reported carbon-based electrocatalysts.

Novel thiophene-bearing conjugated microporous polymer honeycomb-like porous spheres with ultrahigh iodine uptake.

Two conjugated microporous polymers containing thiophene-moieties (SCMPs) were obtained by the polymerization of 3,3',5,5'-tetrabromo-2,2'-bithiophene and ethynylbenzene monomers through the palladium-catalyzed Sonogashira-Hagihara crosscoupling reaction. The resulting SCMPs show high thermal stability with a decomposition temperature above 300 °C. Scanning electron microscopy images show that the resulting SCMPs formed as an aggregation composed of micrometer-sized SCMP spheres, in which honeycomb-like porous spheres with penetrated pores on the surface were observed. Taking advantage of such a unique honeycomb-like porous morphology as well as π-conjugated structures, the SCMPs show ultrahigh absorption performance for iodine vapour with an uptake of up to 345 wt% obtained, which is the highest value reported to date for CMPs, thus making the resulting SCMPs ideal absorbent materials for reversible iodine capture to address environmental issues.

Two-dimensional wavelike spinel lithium titanate for fast lithium storage.

Safe fast-charging lithium-ion batteries (LIBs) have huge potential market size on demand according to their shortened charging time for high-power devices. Zero-strain spinel Li4Ti5O12 is one of ideal candidates for safe high-power batteries owing to its good cycling performance, low cost and safety. However, the inherent insulating characteristic of LTO seriously limits its high-rate capability. In this work, we successfully synthesize novel wavelike spinel LTO nanosheets using a facile 'co-hydrolysis' method, which is superior to molten-salt approach and traditional solvothermal method in some respects. The unique 2D structures have single-crystal framework with shortened path for Li ion transport. As a result, the N-doped 2D wavelike LTO with 0.6 wt.% of 'carbon joint' not only exhibits exciting capacity of ~180 and ~150 mA h g(-1) for fast lithium storage at high discharge/charge rates of 1.7 and 8.5 A g(-1) (10C and 50C) respectively, but also shows excellent low-temperature performance at -20°C. In addition, the cost may be further decreased due to recycled functional reagents. This novel nanostructured 2D LTO anode material makes it possible to develop safe fast-charging high-power lithium ion batteries.

Ultrathin Wrinkled N-Doped Carbon Nanotubes for Noble-Metal Loading and Oxygen Reduction Reaction.

We describe the fabrication of ultrathin wrinkled N-doped carbon nanotubes by an in situ solid-state method. The positions of Co catalyst were first labeled by good-dispersion and highly loaded Au and Pt, indicating the most of Co are unsealed. The resultant unique nanoarchitecture, which exhibits the features of carbon nanotube and graphene with a combined effect of 1D and 2D carbon-based nanostructures, exhibited a superior ORR activity to carbon nanotubes and graphene. Moreover, the novel catalysts showed a better durability and higher tolerance to methanol crossover and poisoning effects than those of Pt/C.