Efficient and Stable Inverted Perovskite Solar Modules Enabled by Solid-Liquid Two-Step Film Formation.

A considerable efficiency gap exists between large-area perovskite solar modules and small-area perovskite solar cells. The control of forming uniform and large-area film and perovskite crystallization is still the main obstacle restricting the efficiency of PSMs. In this work, we adopted a solid-liquid two-step film formation technique, which involved the evaporation of a lead iodide film and blade coating of an organic ammonium halide solution to prepare perovskite films. This method possesses the advantages of integrating vapor deposition and solution methods, which could apply to substrates with different roughness and avoid using toxic solvents to achieve a more uniform, large-area perovskite film. Furthermore, modification of the NiOx/perovskite buried interface and introduction of Urea additives were utilized to reduce interface recombination and regulate perovskite crystallization. As a result, a large-area perovskite film possessing larger grains, fewer pinholes, and reduced defects could be achieved. The inverted PSM with an active area of 61.56 cm2 (10 × 10 cm2 substrate) achieved a champion power conversion efficiency of 20.56% and significantly improved stability. This method suggests an innovative approach to resolving the uniformity issue associated with large-area film fabrication.

High-entropy NiFeCoV disulfides for enhanced alkaline water/seawater electrolysis.

Creating electrocatalysts with high activity and stability to meet the needs of highly effective seawater splitting is of great importance to achieve the goal of hydrogen production from abundant seawater source, which however is still challenging owing to sluggish oxygen evolution reaction (OER) dynamics and the existed competitive chloride evolution reaction. Herein, high-entropy (NiFeCoV)S2 porous nanosheets are uniformly fabricated on Ni foam via a hydrothermal reaction process with a sequential sulfurization step for alkaline water/seawater electrolysis. The obtained rough and porous nanosheets provide large active surface area and exposed more active sites, which can facilitate mass transfer and are conducive to the improvement of the catalytic performance. Combined with the strong synergistic electron modulation effect of multi elements in (NiFeCoV)S2, the as-fabricated catalyst exhibits low OER overpotentials of 220 and 299 mV at 100 mA cm-2 in alkaline water and natural seawater, respectively. Besides, the catalyst can withstand a long-term durability test for more than 50 h without hypochlorite evolution, showing excellent corrosion resistance and OER selectivity. By employing the (NiFeCoV)S2 as the electrocatalyst for both anode and cathode to construct an overall water/seawater splitting electrolyzer, the required cell voltages are only 1.69 and 1.77 V to reach 100 mA cm-2 in alkaline water and natural seawater, respectively, showing a promising prospect towards the practical application for efficient water/seawater electrolysis.

Modification of spinel MnCo2O4 nanowire with NiFe-layered double hydroxide nanoflakes for stable seawater oxidation.

Currently, direct electrolysis of seawater-based electrolytes rather than fresh water based ones for hydrogen production is gaining more and more attentions for creating a sustainable society. However, using seawater remains more challenges owing to the existence of competitive reactions between chlorine evolution reaction (ClER) or hypochlorite generation reaction and oxygen evolution reaction (OER) and electrode erosion. In this study, a MnCo2O4 nanowire coated with NiFe-Layered Double Hydroxide (NiFe-LDH) layer (MnCo2O4@NiFe-LDH) composite electrocatalyst prepared by a simple two-step hydrothermal method was applied for the seawater electrolysis, which exhibited low overpotentials of 219 and 245 mV at a relatively high current density of 100 mA cm-2 in alkaline simulated and natural seawaters, respectively, as the anode electrocatalyst. It is found that the NiFe-LDH layer on the MnCo2O4 nanowire can serve as Cl- protective layer to hinder the ClER and anode erosion and simultaneously improve the active surface area and intrinsic properties of MnCo2O4 nanowires, allowing for faster kinetics. While, the high valence states of Mn3+, Co3+, Ni3+and Fe3+ played a vital role for OER. In addition, when it was used as the bifunctional electrocatalyst for the overall real seawater splitting, the cell composed of MnCo2O4@NiFe-LDH (-) || MnCo2O4@NiFe-LDH (+) pair only required a low voltage of 1.56 V@10 mA cm-2 and simultaneously maintained excellent stability at a high current density of 100 mA cm-2. Such an electrocatalyst could be a promising candidate for long-term seawater splitting.

A poly(ether block amide) based solid polymer electrolyte for solid-state lithium metal batteries.

Solid-state lithium (Li) metal batteries (SSLMBs) with high-energy density and high-security are promising for energy storage application and electronic device development. However, Li dendrite generation is still one of the most important factors hindering the application of SSLMBs since interface contact degradation, dead Li accumulation, and continuous solid-electrolyte interphase (SEI) growth are always caused by Li dendrite growth, making the performances of SSLMBs deteriorate rapidly. In this study, a poly(ether block amide) (PEBA) based polymer electrolyte with lithium bis-(trifluoromethanesulfonyl)imide (LiTFSI) as the Li salt is developed. It is found that the PEBA 2533-20% LiTFSI electrolyte possesses an ion conductivity of 3.0 × 10-5 S cm-1 at 25 °C. Especially, the Li dendrite suppression ability of SEI is greatly enhanced since it provides abundant amide groups to activate TFSI- anions and further enriches lithium fluoride (LiF) content in the SEI layer, which endows the full-cell with enhanced cyclability. As a result, the fabricated solid-state Li/PEBA 2533-20% LiTFSI/LiFePO4 (areal capacity: 0.15 mAh cm-2) battery remains 94% of its maximum capacity (127.5 mAh g-1) at a rate of 0.5C and 60 °C after 200 cycles. In particular, the full cell can cycle for almost 1000 times without short circuit. Therefore, the PEBA based electrolyte could promote the LiF enriched SEI layer into a platform to suppress the growth of Li dendrite toward SSLMBs with a long-life span.

Nanosheet-state cobalt-manganese oxide with multifarious active regions derived from oxidation-etching of metal organic framework precursor for catalytic combustion of toluene.

For the first time, a nanosheet-state CoMnx mixed oxide with multifarious active regions was synthesized by oxidation-etching assembly of metal organic framework (MOF) precursor and applied for catalytic combustion of toluene at low temperatures. The obtained optimum catalyst denoted as CoMn6 showed excellent performance, which achieved 90% conversion of 1,000 ppm toluene under a weight hourly space velocity (WHSV) of 60,000 mL/(g·h) at 219 °C. While, it also exhibited long-term stability with strong water resistance property. The characterizations of physicochemical properties indicated that the oxidation-etching assembly process built an abundant mesoporous structure in the CoMnx catalyst, which greatly increased the specific surface area (SSA). Especially, potassium permanganate as oxidant and manganese source led to uniform dispersion and assembling of cobalt atoms, which caused the generation of low-crystallinity CoMnx mixed oxide with abundant dislocations, vacancies, phase interfaces and amorphous structures, resulting in excellent low-temperature reducibility, outstanding lattice oxygen mobility and abundant active species such as Mn3+, Co3+ and adsorbed oxygen species. Density functional theory (DFT) calculations demonstrated that gaseous oxygen with the longer bond length (1.406 Å) and stronger adsorption energy (-4.443 eV) could be adsorbed and activated well on the MnCo2O4.5 (311) plane, which is beneficial for the toluene oxidation. In situ diffuse reflectance infrared spectroscopy (DRIFTS) technique was applied to track the intermediates of toluene combustion under different atmospheres, which further deduced the contributions of different active regions and oxidation mechanism over the CoMnx catalyst. The present facile strategy of oxidation-etching assembly of the MOF precursor for the creating of novel catalyst with high performance could be applied in a wide variety of materials besides VOC combustion catalysts.

Trimetallic sulfides derived from tri-metal-organic frameworks as anode materials for advanced sodium ion batteries.

Highly conductive metal sulfides with high theoretical capacities and good conductivity have been considered as anode material alternatives for sodium-ion batteries (SIBs). Unfortunately, the unsatisfactory cycling stability and poor rate performance are usually resulted from the sluggish electrochemical kinetics and volumetric expansion in the charge/discharge process, which severely restricts their applications. Herein, trimetallic sulfides embedded into the carbon matrix with a microsphere shape (denoted as CoNiZnS/C) were successfully prepared by a facile solid sulfidation of tri-metal-organic frameworks. The nanorods-assembled microsphere structure with abundant phase boundaries of multiphase in the CoNiZnS/C would provide abundant active sites and defects for storing sodium ions and rich voids to alleviate the volumetric strains. As the anode material of SIBs, the optimum composite named as CoNiZnS/C-2 in this work demonstrated high initial Coulombic efficiency (96.52% at 0.1 A g-1), good cycling stability (maintaining 410.7 mA h g-1 at the 960th cycle at 2.0 A g-1) and excellent rate performance (477.0 mA h g-1 at 5.0 A g-1). Thus, such a multi-metal sulfide composite with special physical-chemical properties may offer a new insight to promote the electrochemical performance of sulfide-based anode materials for the SIBs.

Foldable nano-Li2MnO3 integrated composite polymer solid electrolyte for all-solid-state Li metal batteries with stable interface.

All-solid-state lithium-ion batteries (ASSLBs) are considered as the most promising next-generation energy storage devices. In this work, a low-cost foldable nano-Li2MnO3 integrated Poly (ethylene oxide) (PEO) based composite polymer solid electrolyte (CPSE) is prepared by simply solid-phase method. Density functional theory calculations indicate that the LMO could provide faster ion transfer channels for the migration of lithium ions between PEO chains and segments. As such, the CPSE obtained has a high ionic conductivity of 5.1 × 10-4 S cm-1 at 60 °C with a high lithium ions transference number of 0.5. The CPSE remains stable even at high temperature with no heat escaping. This could improve the safety performance of the batteries. As a result, the lithium metal battery assembled with CPSE works stably after over 200 cycles at a high rate of 0.5C, and its specific capacity is as high as 125 mAh g-1. Also, it is confirmed that this CPSE adapts to three cathode materials. The Li metal pouch battery assembled with the CPSE is foldable and has excellent mechanical properties. All these results indicate that the CPSE obtained has excellent electrochemical and outstanding safety performances, which can make it have broad commercial applications in ASSLBs.

Microwave-assisted synthesis of manganese oxide catalysts for total toluene oxidation.

Oxygen vacancy on the heterogeneous catalyst is of great importance to the catalysis of volatile organic compound (VOC) oxidation. Herein, microwave radiation with special energy-excitation is successfully utilized for the post-processing of a series of manganese oxides (MnOx) to generate oxygen vacancies. It is found that the MnOx catalyst with 60 min of microwave radiation demonstrates higher activity for toluene oxidation with a T50% of 210 °C and a T100% of 223 °C, which is attributed to the higher concentration of oxygen vacancies derived from the rich phase interface defects resulted from the microwave radiation. Furthermore, the Mn-MW-60 catalyst possesses excellent thermal stability and water vapor tolerance even under 20 vol% H2O atmospheres within 60 h. In situ DRIFTS analysis verifies that both surface and lattice oxygen species simultaneously participate the oxidation process, and all reactions over different environments follows two different pathways. Meanwhile, it is proposed that those oxygen vacancies derived from microwave radiation could facilitate the rate-controlling step of opening the aromatic ring based on the electron back-donation, thereby leading to the increment of catalytic activity.

Trace holmium assisting delaminated OMS-2 catalysts for total toluene oxidation at low temperature.

In this study, octahedral molecular sieve (OMS-2) is successfully delaminated by using trace holmium (Ho) via a facile redox co-precipitation route, which exhibits high performance for the total toluene oxidation at low temperature. High resolution transmission electron microscope (HRTEM), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) analyses verify that abundant multi-phase interfaces and lattice dislocations are formed on the obtained delaminated OMS-2 by the Ho (Ho-OMS-2), which can induce more active oxygen species. In particular, the delaminated OMS-2 with a trace Ho amount has a high Oads/Olatt ratio with a balanced ratio of Mn3+ and Mn4+, demonstrating much higher activity (T100% of 228 °C even under 5 vol% H2O vapor over 0.5% Ho-OMS-2) than the parent OMS-2 (T100% of 261 °C) for the total toluene oxidation. Furthermore, the positive effect of the introduction of H2O on catalytic activity, especially the enhancement of the conversion of intermediates into CO2 and H2O, is verified by the in situ diffuse reflection infrared Fourier transform spectroscopy (DRIFTS). Based on these results, the reaction mechanism for toluene oxidation over the OMS-2 based catalyst is proposed. It is expected to provide an effective preparation method to obtain high-performance catalysts for the VOCs oxidation at low temperatures.

In-situ catalytic upgrading of bio-oil from rapid pyrolysis of biomass over hollow HZSM-5 with mesoporous shell.

To solve the issue of narrow micropores in traditional protonic type Zeolite Socony Mobil-5 (HZSM-5) catalysts in the restricting of large-molecular reactants/products diffusion, hollow HZSM-5 with a mesoporous shell was prepared using a hydrothermal method combined with a tetrapropylammonium hydroxide (TPAOH) treatment process. Applying for in-situ catalyst upgrading of bio-oil from rapid pyrolysis of biomass, the obtained most efficient catalyst of Hollow(30)-TP resulted in aromatic hydrocarbon yields in the range of 78.49-78.67% for cellulose and hemicellulose, which is much greater than those using the traditional HZSM-5 (61.06-68.26%). Furthermore, in the case using real biomass (cedar) with an optimal biomass/catalyst weight ratio of 1:2, the aromatic hydrocarbon yield reached up to 80.16%. In addition, this catalyst exhibited excellent reusability and regeneration property due to the increased accessibility to the acid sites in the hollow HZSM-5 for the improving of the reaction rate as well as the reducing of coking.

Controllable Synthesis of Novel Orderly Layered VMoS2 Anode Materials with Super Electrochemical Performance for Sodium-Ion Batteries.

Sodium-ion batteries (SIBs), being an attractive candidate of lithium-ion batteries, have attracted widespread attention as a result of sufficient sodium resource with low price and their comparable suitability in the field of energy storage. However, one of the main challenges for their wide-scale application is to develop suitable anode materials with excellent electrochemical performance. Herein, a novel orderly layered VMoS2 (OL-VMS) anode material was synthesized through a facile hydrothermal self-assembly approach followed by a heating procedure. As the anode material of the SIBs, the unique structure of OL-VMS not only facilitated the rapid migration of sodium ions between the stacked layers but also provided a stable framework for the volume change in the process of intercalation/deintercalation. In addition, vanadium mediating in the framework caused more defects to produce abundant storage sites for Na+. As such, the obtained OL-VMS-based anode exhibited high reversible capacities of 602.9 mAh g-1 at 0.2 mA g-1 and 534 mAh g-1 even after 190-cycle operation at 2 A g-1. Furthermore, the OL-VMS-based anode delivered an outstanding specific capacity of 626.4 mAh g-1 after 100-cycle testing at 2 A g-1 in a voltage range from 0.01 to 3 V. In particular, even in the absence of conductive carbon, it still showed an excellent specific capacity of 260 mAh g-1 at 1 A g-1 after 130 cycles in a 0.3-3 V voltage range, which should contribute to the cost reduction and energy density increase.

Hydrogen-rich gas production from steam co-gasification of banana peel with agricultural residues and woody biomass.

Steam co-gasification of banana peel with other biomass, i.e., Japanese cedar wood, rice husk and their mixture, was carried out for the hydrogen-rich gas production in a fixed-bed reactor. For the co-gasification process, the banana peels were physically mixed with rice husk, Japanese cedarwood and their mixture respectively by different mixing weight ratios. The effects of reaction temperature and the addition amount of banana peel on the gas production yield were investigated by comparing the experimental data with the calculated ones based on the individual biomass gasification at the same condition. It was found that the banana peel with a high content of alkali and alkaline earth metal (AAEM) species exhibited not only high gasification reactivity but also a significant enhancing catalytic effect on the co-gasification process at the low temperature, especially with the biomass containing no silica species. The high content of silica species in the rice husk had a negative effect on the gasification reactivity of banana peel during the co-gasification since it could hinder the release of AAEM from the biomass and/or lead to the possible formation of inactive alkaline silicates. However, the combination of these three samples with the suitable weight ratio could improve the gasification performance at the low temperature due to the synergetic effect provided by high contents of potassium and calcium from banana peel and cedarwood respectively. Moreover, the addition of calcined seashells as the CaO source could further improve the gas production yield, especially the hydrogen gas yield at a relatively low gasification temperature of 750 ℃.

Adsorptive removal and photocatalytic decomposition of cationic dyes on niobium oxide with deformed orthorhombic structure.

Nano-rod-shaped niobium oxide with a deformed orthorhombic structure (ortho-Nb2O5) is first demonstrated as a selective adsorbent to remove cationic dyes wastewater. Ortho-Nb2O5 quickly adsorbs methylene blue (MB) with much greater capacity than reported inorganic adsorbents. Furthermore, ortho-Nb2O5 has a stronger affinity to cationic dye than anionic dye because cation exchange is involved in the adsorption process. The dye molecule adsorbed onto ortho-Nb2O5 can be degraded entirely under UV light irradiation because of its photocatalytic properties. Moreover, the regenerated ortho-Nb2O5 shows high reusability for use in additional adsorption processing. As described herein, new insights into the use of ortho-Nb2O5 as a photocatalytically regeneratable adsorbent for wastewater treatment are presented.

Biomass-Derived N-Doped Carbon for Efficient Electrocatalytic CO2 Reduction to CO and Zn-CO2 Batteries.

Conversion of CO2 into valuable chemicals via electrochemical CO2 reduction reaction (CO2RR) is a promising technology to alleviate the energy crisis and the greenhouse effect. Herein, low-cost wood biomass was applied as the carbon source to prepare nitrogen (N)-doped carbon electrocatalysts for the conversion of CO2 to CO and further as the cathode material for Zn-CO2 batteries. By virtue of N-doping and assistance of FeCl3, a cedar biomass-derived three-dimensional (3D) N-doped graphitized carbon with a high N-doping content (5.38%), an ultrahigh specific surface area (1673.6 m2 g-1), rich nanopores, and sufficient active N sites was successfully obtained, which exhibited super CO2RR activity with a high faradaic efficiency of 91% at a low applied potential of 0.56 V (vs RHE) and a long-term stability for at least 20 h. Furthermore, a Zn-CO2 battery with it as the cathode material delivered a stable open circuit voltage of 0.79 V, a peak power density of 0.51 mW cm-2 at 2.14 mA cm-2, and a maximum faradaic efficiency to CO of 80.4% at 2.56 mA cm-2, indicating that it could be applied in a practical process by using CO2 to generate power with the production of CO. Density functional theory calculations revealed that pyridinic N could more effectively decrease the free energy barriers for CO2RR and boost the reaction. This work not only revealed a facile approach to convert waste biomass into N-doped-graphitization carbon as valuable CO2RR electrocatalysts but also provided a new strategy to achieve "carbon solving carbon's problem".

Fabrication of a High-Energy Flexible All-Solid-State Supercapacitor Using Pseudocapacitive 2D-Ti3C2Tx-MXene and Battery-Type Reduced Graphene Oxide/Nickel-Cobalt Bimetal Oxide Electrode Materials.

Owing to excellent metallic conductivity, hydrophilic surfaces, and surface redox properties, a two-dimensional (2D) metal carbide of Ti3C2Tx-MXene could serve as a promising pseudocapacitive electrode material for energy storage devices. Meanwhile, the 2D reduced graphene oxide (rGO) combining with the hierarchical cubic spinel nickel-cobalt bimetal oxide (NiCo2O4) nanospikes could control ion diffusion for charge storage, thereby facilitating the improvement of the energy density of a supercapacitor. As per the strategy, the pseudocapacitive 2D Ti3C2Tx was loaded on a flexible acid-treated carbon fiber (ACF) backbone to prepare a Ti3C2Tx/ACF negative electrode by a convenient drop-casting method. Meanwhile, 2D rGO was deposited on ACF by a simple dip-dry process, which was further decorated by the spinel NiCo2O4 nanospikes using a hydrothermal method to obtain a NiCo2O4@rGO/ACF positive electrode. The fabricated Ti3C2Tx/ACF electrode exhibited an excellent specific capacitance of 246.9 F/g (197.5 mF/cm2) at 4 mA/cm2 along with 96.7% capacity retention over 5000 charge/discharge cycles, whereas the NiCo2O4@rGO/ACF electrode showed a specific capacitance of 1487 F/g (458.3 mA h/g) at 3 mA/cm2 with a cycling stability of 88.2% over 10 000 charge/discharge cycles. As a result, a flexible all-solid-state hybrid supercapacitor (FHSC) device using the pseudocapacitive Ti3C2Tx/ACF on the negative side with a widespread voltage window and the battery-type NiCo2O4@rGO/ACF on the positive side with high electrochemical activity delivered an excellent volumetric capacitance of 2.32 F/cm3 (141.9 F/g) at a current density of 5 mA/cm2 with a high-energy density of 44.36 Wh/kg (0.72 mWh/cm3) at a power density of 985 W/kg (16.13 mW/cm3) along with a cycling stability of 90.48% over 4500 charge/discharge cycles. Therefore, the pseudocapacitive 2D Ti3C2Tx/ACF negative electrode could replace carbon-based electrodes and a combination of it with the battery-type NiCo2O4@rGO/ACF positive electrode should be a promising way to step up the energy density of a supercapacitor.

Electroactive magnetic microparticles for the selective elimination of cesium ions in the wastewater.

To improve operability as well as the removal efficiency for cesium ions in the wastewater treatment, a novel electrochemically switched ion exchange (ESIX) technique by using electroactive Prussian-blue(PB)-based magnetic microparticles (PB@Fe3O4 microparticle) with different uniform particle sizes in the range of 300-900 nm as the adsorption materials was developed. The obtained PB@Fe3O4 microparticle were characterized by Scanning electron microscopy (SEM), Transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Thermogravimetric analysis (TGA). It is found that the PB can be well coated on the surface of Fe3O4 microsphere, which can be easily adsorbed on the magnetic electrode substrate for the electrochemical adsorption of Cs+ ions. Electrochemical adsorption of 97% Cs+ on PB/Fe3O4 was achieved in less than 10 min, and the maximum adsorption capacity was 16.13 mg/g, and the distribution coefficient (KD) of Cs+ ions reached as high as 3938. In addition, the electrochemical adsorption behavior of PB@Fe3O4 microparticle fitted well with the Freundlich adsorption isotherm and the Pseudo-second-order kinetic models. It is expected that such an ESIX technique using PB@Fe3O4 microparticle can be applied for the separation and recovery of dilute Cs+ ions from cesium-contaminated solution in a practical process.

Engineering interfacial structures to accelerate hydrogen evolution efficiency of MoS2 over a wide pH range.

Developing low-cost electrocatalysts with outstanding electrochemical performance for water splitting over a wide pH range is urgently desired to meet the practical needs in different areas. Herein, a highly efficient hierarchical flower-like CoS2@MoS2 core-shell nanostructured electrocatalyst is fabricated by a two-step strategy, in which MoS2 nanosheets with a layered structure are grown on the CoS2 core supported on carbon paper (CP) and used as hydrogen evolution reaction (HER) electrocatalysts working in the whole pH range (0-14). Remarkably, benefiting from the interface-engineering in this 3D core-shell structure of the electrocatalyst, the optimum CoS2@MoS2/CP catalyst exhibits outstanding HER activity over a wide range of pH values and an overpotential of 69 mV in acidic solution, 145 mV in neutral solution and 82 mV in alkaline solution, respectively, to afford the standard current density of 10 mA cm-2. Furthermore, it demonstrates superior stability under different pH conditions for at least 48 h. Density functional theory (DFT) calculations are performed to gain further insight into the effect of CoS2@MoS2 interfaces, revealing that the strong interfacial interaction between CoS2 and MoS2 dramatically reduces the Gibbs free energy of hydrogen adsorption and the energy barrier for water dissociation, thus enhancing the electrochemical HER activity in the whole pH range (0-14).

Nickel phosphate nanorod-enhanced polyethylene oxide-based composite polymer electrolytes for solid-state lithium batteries.

Solid-state electrolytes with high ionic conductivity, large electrochemical window, and excellent stability with lithium electrode are needed for high-energy solid-state lithium batteries. In this work, a novel polyethylene oxide (PEO)-Lithium bis(trifluoromethylsulphonyl)imide (LiTFSI)-nanocomposite-based polymer electrolyte was prepared by using nickel phosphate (VSB-5) nanorods as the filler. The ionic conductivity of the obtained PEO-LiTFSI-3%VSB-5 solid polymer electrolyte was found to be as high as 4.83 × 10-5 S·cm-1 at 30 °C and electrochemically stable up to about 4.13 V versus Li/Li+. The enhanced ionic conductivity was attributed to the reduced crystallinity of the PEO and the interaction between VSB and 5 and PEO-LiTFSI. In addition, the solid polymer electrolyte exhibited improved compatibility to the lithium metal anode with excellent suppression of lithium dendrites. The assembled LiFePO4/Li battery with the PEO-LiTFSI-3%VSB-5 solid polymer electrolyte showed better rate performance and higher cyclic stability than the PEO-LiTFSI electrolyte. It is demonstrated that this new solid polymer hybrid should be a promising electrolyte applied in solid state batteries with lithium metal electrode.

Bi-Doped SnO Nanosheets Supported on Cu Foam for Electrochemical Reduction of CO2 to HCOOH.

Design and fabrication of efficient electrocatalysts is essential for electrochemical reduction of carbon dioxide (CO2). In this work, bismuth (Bi)-doped SnO nanosheets were grown on copper foam (Bi-SnO/Cu foam) by a one-step hydrothermal reaction method and applied for the electrochemical reduction of CO2 to formic acid (HCOOH). The experimental results indicated that Bi doping stabilized the divalent tin (Sn2+) existing on the surface of the electrocatalyst, making it difficult to be reduced to metallic tin (Sn0) during the electrochemical reduction process. In addition, combining with density functional theory (DFT) calculations, it is found that Bi doping and electron transfer from the catalyst to the Cu foam substrate could enhance the adsorption of *OOCH intermediates. As such, the Bi-doped SnO electrocatalyst exhibited a superior faradaic efficiency of 93% at -1.7 V (vs Ag/AgCl) for the reduction of CO2 to HCOOH, together with a current density of 12 mA cm-2 and excellent stability in at least 30 h of operation.

Fabrication and evaluation of nanocellulose sponge for oil/water separation.

Nanocellulose sponge was fabricated by a facile method: freeze-drying of nanocellulose aqueous suspension to sponge state, following by hydrophobic treatment with stearoyl chloride at 50 °C for 1 h. The obtained nanocellulose sponge showed superhydrophobicity (160° of water contact angle) and superoleophilicity with high protection from water but selective absorption of oil. Its absorption capacities for various kinds of oil and non-polar liquids were 25-55 times higher than its dry weight and exhibited excellent selectivity for absorbing of oil which spilled on the surface of water or underwater with high separation efficiency. This superhydrophobic nanocellulose sponge can be easily recovered by simple squeezing and reused at least 10 cycles with remained high separation efficiency. It is expected that such a biodegradable nanocellulose sponge can be applied to solve the oil spill accident and treat the oily wastewater from households and industries.