The electrochemical performance of all-solid-state Li metal batteries (ASSLMBs) can be improved by resolving the challenges triggered by the uncontrolled growth of Li dendrites throughout the solid electrolytes (SEs). Herein, a well-defined composite of micro-Li6PS5Cl (LPSC) and nano-Li1.3Al0.3Ti1.7(PO4)(3) (LATP) is designed as a LPSC-LATP interlayer sandwiched between LPSC electrolytes for ASSLMBs. This fabrication exhibits electron-blocking functionalities, which reduce the probability of reaction with Li+ ions for the formation of anode-initiated and grain boundary (GB)-initiated dendrites. More importantly, it also creates localized eliminated micro-environments of Li dendrites through the high transient reactivity between them, and the remaining cracks can be dynamically and effectively filled by decomposition products, thereby clearly suppressing Li dendrite nucleation, propagation and penetration as well as simultaneously contributing to the enhancement of battery performance and stability. With this approach, a fine-tuned LPSC-LATP (8S-2O) interlayer enables symmetrical Li/LPSC/8S-2O/LPSC/Li cells to achieve an ultra-high critical current density (CCD) of over 5 mA cm(-2) at room temperature, and ultra-long-term cycling at a current density of 10 mA cm(-2) for over 1600 h. Additionally, ASSLMBs employing commercial LiCoO2 cathodes can deliver exceptional durability, with an extremely high 85.6% retention of initial discharge capacity and coulombic efficiency (CE) of >99.6% after 1200 cycles at 1C (1.28 mA cm(-2)). These experimental batteries demonstrate the application potential of this configuration of SEs for the commercialization of ASSLMBs.

The defect engineering is of vital importance for electrocatalysts because it can provide an additional yet advanced tier to further boost catalysis, especially for ultrathin nanosheets of transitional metal compounds with a high surface to bulk ratio and more importantly the ability to engineer the defect along the longitudinal direction of the grain boundaries. Herein, we developed super-thin and ordered face-centered cubic VN nanosheets with grain boundaries using a new facile and in-situ method. The structural and morphological properties of the prepared samples were investigated, finding that the temperature has significant effects on the distribution of sheets. The thickness of nanosheets is only 1.3 nm the same as that of three cubic VN crystal unit cells, which is pivotal to the electrochemical reaction. The detailed electrocatalysts results show that the VN nanosheets (NSs) exhibit interesting ORR performance with the onset potential of 0.93 V and a half-wave potential of 0.86 V. The evenly distributed VN NSs display the highest durability with only 5% attenuation after 50000s operation for the oxygen reduction reaction. We provide a new strategy to synthesize super-thin nitrides nanosheet structure, highlighting the strong correlation between surface engineering and the performance of electrocatalysts for potential practical oxygen reactions.

Ni 3 P@Ni/CNP exhibits excellent OER electrocatalytic activity. The current density of 10 mA cm −2 in 1 M KOH electrolyte only needs an overpotential of 239 mV in the presence of the catalyst, and it showed excellent stability.

Exploring economically efficient electrocatalysts with robust oxygen reduction catalytic activities and developing appropriate structures are necessary to understand fuel cells with high open-circuit voltages and long lifespans. In this work, a high-performance ORR catalyst was prepared with a one-spot method by pyrolysis of a urea, FeCl 3 , and NaCl mixture. The surface element distribution was studied by XPS etching, showing the active sites ɛ-Fe 3 N with active Fe-N bonding. Benefiting from the double layer protection, in which the ɛ-Fe 3 N nanoparticles were covered by a N-doped carbon layer encapsulated in carbon bamboo-like nanotubes, the catalysts showed an abnormal stability with 5000 cycles, a negative shift of only 15 mV by the CV test and a 3% attenuation after 60000 s of operation. The onset potential is found to be 0.96 V, which is a positive shift of 12 mV compared to that of the state-of-the-art Pt/C catalyst. The ORR kinetic analysis indicates that the catalyst shows a Tafel slope of 82 mV decade -1 at high potential and 130 mV decade -1 at low potential close to that of the reference catalyst, suggesting a similar reaction mechanism. Therefore , successfully synthesized nonnoble electrocatalysts offer a novel strategy and promising candidates to promote the further development of clean energy devices.

The oxygen evolution reaction (OER) is of fundamental importance as a half reaction and rate-controlling step that plays a predominant function in improving the energy storage and conversion efficiency during the electrochemical water-splitting process. In this review, after briefly introducing the fundamental mechanism of the OER, we systematically summarize the recent research progress for nonprecious-metal-based OER electrocatalysts of representative first-row transition metal (Fe, Co and Ni)-based composite materials. We analyze the effects of the physicochemical properties, including morphologies, structures and compositions, on the integrated performance of these OER electrocatalysts, with the aim of determining the structure-function correlation of the electrocatalysts in the electrochemical reaction process. Furthermore, the prospective development directions of OER electrocatalysts are also illustrated and emphasized. Finally, this mini-review highlights how systematic introductions will accelerate the exploitation of high-efficiency OER electrocatalysts.

Sulfide-type solid electrolytes (SSEs) are supposed to be preferential candidates for all-solid-state Li metal batteries (ASSLMBs) due to their satisfactory Li+ conductivity and preferable mechanical stiffness. Nonetheless, the poor stability between the Li anode and SSEs and uncontrolled Li dendrite growth severely restrict their commercial application. Herein, an amphiphilic LixSiOy-enriched solid electrolyte interphase (SEI) as a "Janus" layer was first introduced at the Li/SSEs interface, and it exhibited bond coupling reactivity with both the Li anode and SSEs by forming Li-S, Li-O-Si, and Si-S covalent bonds, which is called the pincer effect. In addition to the physical isolation of Li and SSEs to prevent side reactions between them, LixSiOy with high ionic conductivity offers abundant and evenly distributed transport channels for fast Li+ migration. As evidenced by in situ microscopy, the high-strength anodic interface constructed by the pincer effect and in situ decomposition mentioned above is free from mechanical damage during the Li plating/stripping. As a result, the symmetric cells exert an outstanding cycling performance for over 2000 h at 0.2 mA cm-2 and even 500 h at 0.5 mA cm-2 without evident resistance growth. The artificial SEI layer with the pincer effect and its effective application in interfacial stabilization put forward a new perspective for the commercialization of ASSLMBs.

Ultrathin nanosheets of transitional metal nitrides are very fundamentally and technologically interesting, and are used in many energy transformation devices. However, synergistical structure and active sites for energy transformation remain challenging. Herein, we developed superthin and ordered face-centered cubic phase vanadium nitride (VN) nanosheets grown on g-C 3 N 4 support using a new facile and in-situ pyrolysis method. Interestingly, the ordered VN nanosheets with the thickness of only 1.3 nm the same as that of three VN unit cells expose a high density of active sites . The as-prepared sample shows comparable oxygen reduction reaction (ORR) catalytic activities (the onset potential of 0.93 V and the half-wave potential of 0.86 V), and only a 10 mV negative shift after the 50000 s corporation in alkaline medium, which should be ascribed to the excellent conductivity of g-C 3 N 4 , the superthin VN nanosheets with rich active sites. Therefore, this work provides a new and effective strategy to synthesize superthin nitride nanosheet structures with superior ORR performance.

Metal sulfide arrays can store electrochemical energy owing to their high theoretical capacity, shortened diffusion routes, and rich electrochemical sites. However, their sluggish redox reaction has limited further application in high power density devices. Herein, a novel hybrid and hierarchical nanostructure with a thin layer of NiO deposited on the surface of walnut-like CoS particles is constructed and the NiO layer can greatly improve the capacitive properties of cobalt sulfide. In this hybrid nanostructure, the amount of NiO on the surface of CoS is precisely tuned to boost the electrochemical performance. Consequently, NiO/CoS exhibits a higher capacitance/capacity of 1749 F g-1/243.9 mAh g-1 fueled by the excellent electrical conductivity and appropriate surface structures. When assembled into a hybrid supercapacitor, the NiO/CoS//AC devices deliver a maximum capacitance of 60 C g-1 at 1.0 A g-1. Energy density reaches 45 Wh kg-1 when the power density is at 750 W kg-1. Additionally, the fabricated supercapacitor has good cycling stability with a capacity retention rate of 74% after 5000 cycles.

ZnO nanomaterials with the stereochemical structure were becoming a research focus in the scope of photocatalytic materials, but the ZnO was sensitive to UV light rather than the solar light source, which considerably prohibited its extended application. ZnO nanomaterials coupled with other nanomaterials could generate the alternative composite heterojunction nanomaterials to promote the photocatalytic activity. Herein, we reported two facile and feasible synthesis methods to fabricate TiO 2 /ZnO cube nanocomposites and Ag/ZnO hollow spheres by hydrothermal reaction and chemical deposition, respectively. In this regard, these composited nanomaterials have been successfully fabricated with high purities, good morphology, and crystal structure. Noticeably, in contrast with TiO 2 /ZnO and Ag/ZnO bulk nanocomposites, the Ag/ZnO hollow spheres could offer the higher activity for RhB degradation under the visible light. Moreover, the photocatalytic performance of Ag/ZnO for RhB degradation could be improved synergistically, and the effect of RhB degradation was highest when the Ag mass ratio was modulated at 10% in the sample. Furthermore, it remained a high photocatalytic efficiency even after four cycles. This protocol provided an approvable approach to fabricate efficient photocatalysts with persistent photostability in the wastewater treatment process.

The sulfide‐type solid electrolyte (SSE) is considered a promising candidate for solid‐state lithium metal batteries (SSLMBs) owing to its advantages of superior ionic conductivity. Nevertheless, the incompatibility of the sulfide and lithium metal can result in undesirable interface resistance and rapid Li dendrite growth, which seriously hinders its commercial applications. Herein, inspired by the moderation and long duration of sustained release drug carriers when combined with active pharmaceutical ingredients in the biomedical field, poly (propylene carbonate) (PPC) and lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) gradually interact with a Li anode with constantly decreased Li/SSE interfacial resistance. In addition to intimate contact, the ultrastable LiF‐enriched solid electrolyte interphase (SEI) is in situ formed via a sustained release effect, which suppresses the Li dendrite effectively. As a result, the symmetric cells demonstrate stable cycling performance for 1200 h at a current density of 0.1 mA cm−2 and 300 h at 0.5 mA cm−2. Moreover, LiFePO4/ Li6PS5Cl /Li SSLMB delivers a high discharge capacity of over 132.8 mAh g−1 for 900 cycles at 1C with steady Coulombic efficiency. Therefore, this sustained release mechanism and its initially successful application in interfacial modification increase the potential for commercial applications of SSLMBs.

Developing a cost-effective, efficient, and facile prepared electrocatalyst for oxygen reduction (ORR) and evolution reaction (OER) is critical for a range of renewable energy technologies. Herein, we report unique Co4N nanoparticles loading on g-C3N4 nanotubes (Co4N@CNNT) bifunctional electrocatalyst for OER and ORR by an in-situ method. Highly dispersed Co4N nanoparticles as the active sites gather at the top of the g-C3N4 nanotube (CNNT), while the six-fold cavities from smooth CNNT with an outer diameter of 48 nm and an inner diameter of 22 nm act as anchor sites to preferentially coordinate with the active sites. Benefiting from the distinctive structure features, the intrinsic metallic Co4N@CNNT exhibits high electrocatalytic performances. Electrochemistry studies show that an onset potential of 0.94 V and a half-wave potential of 0.86 V of Co4N@CNNT are obtained that are superior to Pt/C catalyst. A low overpotential of 285 mV at an anodic current density of 10 mA cm-2 during the OER process is obtained that is superior to the IrO2 catalyst; and lower Tafel plot and good durability are also observed. Our findings provide a new strategy for the fabrication of an efficient bifunctional electrocatalyst for OER and ORR.

Binders are of vital importance in stabilizing the cathodes to enhance the cycling stability of lithiumsulfur (Li-S) batteries.However,conventional binders are typically confronted with the drawback of inability for adsorbing lithium polysulfide (LipS),thus resulting in severe active material losing and rapid capacity fading.Herein,a novel water-soluble hyperbranched poly(amidoamine) (HPAA) binder with controllable hyperbranched molecular structure and abundant amino end groups for Li-S battery is designed and fabricated,which can improve efficient adsorption for LiPS and stability of the sulfur cathodes.Besides,the strong intermolecular hydrogen bonds in HPAA binder can contribute to the structural stability of S cathode and integration of the conductive paths.Therefore,the Li-S battery with this functional binder exhibits excellent cycle performance with a capacity retention of 91％ after 200 cycles at 0.1 C.Even at a high sulfur loading of 53 mg cm-2,a specific capacity of 601 mA h g-1 can also be achieved.Density functional theory (DFT) calculation further demonstrates that the enhanced electrochemical stability derives from the high binding energy between amino groups and LiPS and the wide electrochemical window (6.87 eV) of HPAA molecule.Based on the above all,this functional polymer will lighten a new species of binders for eco-friendly sulfur cathodes and significantly promote the practical applications of high-performance Li-S batteries.

The development of earth-abundance electrocatalyst with high performance for oxygen evolution reaction (OER) is of paramount importance in sustainable water splitting. Herein, the novel defect-induced nitrogen-doped carbon-supported Co(3)O(4 )nanoparticles is successfully fabricated as OER electrocatalyst (denoted as Co3O4/CN HNPs) through a wetness-impregnation treatment of Co/polyaniline (PANI) followed by a thermal annealing. This advanced architecture of Co3O4/CN HNPs can not only improve its conductivity and electrocatalytically active sites but also generate a large number of oxygen-vacancy defects and crystal defects, which effectively exert the preponderance in facilitating interfacial electronic transfer and optimizing the adsorption energy for intermediates, thus imparting the extraordinary activities in catalyzing OER. In addition, there are evidences demonstrating the formation of C-N coordination bonds through the strong interaction of the interconnected interface and the generation of pyridinic-N species after the annealing treatment, which enables the structural stability to get further strengthened and accelerates oxygen releasing for reduction of OER overpotential, respectively. Benefiting from the above desirable properties, the Co3O4/CN HNPs affords a lower overpotential of 290 mV at a current density of 10 mA cm(-2) as compared to those of pure Co(3)O(4 )and PANI, outperforming commercial IrO2 and the representative Co3O4-based OER electrocatalysts as recently reported. Moreover, the Co3O4/CN HNPs also exhibits long durability with negligible activity degeneration at a current density of 10 mA cm(-2) for 20 h.-.

Pt-free electrocatalysts for the oxygen reduction reaction (ORR) are valuable with a wide range of applications, but their insufficient activities and stabilities cannot satisfy the commercial requirement. Nitride atomic clusters with the Pt-like electronic structure embedded the conductive and stable g-C3N4 offers an alternative route to promote ORR performance. Herein, we report a facile and in-situ nitriding method to obtain a unique tungsten nitride atomic cluster loaded on the two-dimensional conductive gC(3)N(4) (WN@g-C3N4) catalyst. In this regard, both the generated cubic-phase WN and its high-dispersedatomic clusters over the designed 2D g-C3N4 layer are mainly responsible for the excellent ORR performance. Especially for WN@g-C3N4-750, the onset potential and half-wave potential were 0.92 and 0.86 V vs. RHE respectively, identical to the results obtained for the Pt/C catalyst. The results demonstrated that the cubic-phase WN atomic clusters act as active sites, which positively influences the electrocatalytic performance. We believe that the WN@g-C3N4 catalyst with the superior electrocatalytic activity has a strong potential to replace the commercial Pt/C catalyst. (C) 2020 Elsevier Ltd. All rights reserved.

A multifunctional fluorinated polyimide nanofiber separator for high-performance lithium–sulfur batteries.

The development of commercial lithium–sulfur (Li–S) batteries is typically restricted by the intrinsic drawbacks of the dissolutiion and shuttling of lithium polysulfides (LPS) and the uncontrollable growth of lithium dendrites.

Polyaniline (PANI)-based composite materials have shown to be promising candidates for oxygen evolution reaction (OER) electrocatalysts because of their non-ignorable merits of conductivity, flexibility, durability and environmental friendly. Herein, we develop a facile strategy to realize in-situ assembly of CoOOH nanosheets into the PANI network, which is denoted as Co/PANI HNSs for OER performance. The nitrogen species derived from PANI building blocks can work as bridging sites to preferentially coordinate with Co metal ions, which impart coupling effects between CoOOH nanosheets and PANI as well as the structure stability. Besides the Co-N coordination, the occurred electron delocalization between Co d-orbitals and PANI pi-conjugated ligands can also modulate the electronic structural states of Co/PANI HNSs, enabling the efficient interfacial electron transfer from CoOOH to PANI. In addition, the Co/PANI HNSs possesses a hierarchical porous with both structure of mesopores and macropores that allows electrolyte to be more efficiently transported to the highly oxidative active sites, resulting in fast reaction kinetics. In recognition of these advanced structural characteristics, the Co/PANI HNSs electrocatalyst can give a low overpotential of 291 mV at an anodic current density of 10 mA cm(-2) and a small Tafel slope of 54 mV dec(-1) in 1 M KOH electrolyte as well as a good durability.

The reverse water-gas shift reaction (RWGSR), a crucial stage in the conversion of abundant CO2 into chemicals or hydrocarbon fuels, has attracted extensive attention as a renewable system to synthesize fuels by non-traditional routes. There have been persistent efforts to synthesize catalysts for industrial applications, with attention given to the catalytic activity, CO selectivity, and thermal stability. In this review, we describe the thermodynamics, kinetics, and atomic-level mechanisms of the RWGSR in relation to efficient RWGSR catalysts consisting of supported catalysts and oxide catalysts. In addition, we rationally classify, summarize, and analyze the effects of physicochemical properties, such as the morphologies, compositions, promoting abilities, and presence of strong metal-support interactions (SMSI), on the catalytic performance and CO selectivity in the RWGSR over supported catalysts. Regarding oxide catalysts (i.e., pure oxides, spinel, solid solution, and perovskite-type oxides), we emphasize the relationships among their surface structure, oxygen storage capacity (OSC), and catalytic performance in the RWGSR. Furthermore, the abilities of perovskite-type oxides to enhance the RWGSR with chemical looping cycles (RWGSR-CL) are systematically illustrated. These systematic introductions shed light on development of catalysts with high performance in RWGSR.