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For lithium ion batteries (LIBs), low electronic conductivity of CuO leads to rapid capacity decay and poor structural stability. Herein, we successfully fabricate three-dimensional CuO nanoflake arrays coated Cu foam by facile and efficient electrochemical oxidation. When being applied as anode material for LIBs, the CuO electrodes deliver stable reversible capacities of 523.9 mA h g −1 at 0.5 A g −1 , 376.1 mA h g −1 at 1.0 A g −1 and 322.7 mA h g −1 at 2.0 A g −1 with high coulombic efficiency (>99%) after 100 cycles. A long cycle life of up to 400 cycles at 2.0 A g −1 is also achieved with the retention capacity of 193.5 mA h g −1 . Moreover, the electrode exhibits excellent rate capability and can regain its original capacities as reversing to the low current densities. Noticeably, on-line differential electrochemical mass spectrometry and in situ Raman measurements confirm the formation of solid electrolyte interface film and the conversion mechanism for the CuO electrodes, respectively. The superior lithium storage performance can be attributed to the favorable nanoflake structures with high surface area and the perfect electrical contact between CuO and Cu substrate. [ABSTRACT FROM AUTHOR]

Antimony (Sb) as a low-toxic and cost-effective metal is a promising material to catalyse CO 2 electroreduction to formate with practical viability. However, monometallic Sb suffers from intrinsically low catalytic activity and the competing hydrogen evolution. Here, we report nanoporous Sb-Bi alloys for substantially improving the catalytic activity of Sb and suppressing hydrogen evolution. The optimal Sb-Bi alloy exhibits a maximum Faradaic efficiency of 95.8 % toward formate production, surpassing the 11.6 % of monometallic Sb counterpart. Operating the catalyst in the flow cell demonstrates a formate partial current density of 734 mA cm−2 and cathodic energy efficiency of 59 % at a moderate overpotential of 800 mV, representing a record formate-production performance so far. Experimental and theoretical studies indicate that the Sb-Bi interactions activate Sb sites to selectively stabilize *OCHO intermediates, facilitating CO 2 -to-formate conversion. This work offers insights in manipulating bimetallic interactions to transform inert materials into active catalysts for efficient electrocatalysis. [Display omitted] • Sb-Bi interactions induce electrocatalytic switching from HER to CO 2 ER. • Sb 2 Bi 6 exhibits a maximum formate selectivity of 95.8 % in an H-type cell. • Sb 2 Bi 6 achieves a record formate activity of 734 mA cm−2 in a flow cell. • Sb-Bi interactions facilitate Sb sites to stabilize *OCHO for formate formation. [ABSTRACT FROM AUTHOR]

• A simple liquid Ga assisted-alloying/dealloying strategy to fabricate nanoporous Ag. • The thickness of alloy layer/nanoporous Ag varies with the mass loading of Ga. • The bimodal wire-like and unimodal bulk-like nanoporous Ag is obtained. • The substrate-supported nanoporous Ag exhibits excellent mechanical properties. The substrate-supported nanoporous Ag with controllable thickness and different morphologies (bulk-like and wire-like) is fabricated via the liquid Ga-assisted alloying/dealloying strategy. [Display omitted] Nanoporous metals show great potentials in various applications including catalysis, sensing, actuation and supercapacitors. The liquid Ga-assisted alloying/dealloying strategy is a feasible and scalable way to fabricate substrate-supported nanoporous metals. However, the influence of intrinsic alloying mode and mechanism on the formation and modulation of nanoporous structure has not been thoroughly explored before. In this work, after painting liquid Ga on Ag foil, both the bulk-like Ag 3 Ga (in the Ag-rich zone) and wire-like Ag 3 Ga (in the liquid Ga-rich zone) form owing to the interdiffusion of Ag and Ga atoms. Correspondingly, the bimodal wire-like and unimodal bulk-like nanoporous Ag is obtained because of the structure inheritance during dealloying. In addition, the thickness of alloy layer (nanoporous layer) versus mass loading of liquid Ga follows a good linear relationship. The in-situ X-ray diffraction of dealloying from Ag 3 Ga to nanoporous Ag illustrates no other intermetallic phase appears and the dealloying process can be described by the dissolution-surface diffusion model. More importantly, the substrate-supported nanoporous Ag exhibits excellent mechanical properties which are of great importance to the future applications of nanoporous metals. [ABSTRACT FROM AUTHOR]

Understanding the sodium (Na) chemistry is crucial for development of high-performance sodium ion batteries (SIBs). Nanostructured bismuth (Bi) has shown great potentials as an anode in SIBs, however, the Na storage mechanisms of Bi are still unclear. Herein, the operando X-ray diffraction (XRD) technique was utilized to probe the Na storage mechanisms of three Bi anodes (sputtered Bi film, nanoporous Bi and commercial Bi). Despite different morphologies and sizes, all the Bi anodes follow the same two-step reversible alloying/dealloying mechanisms (Bi ↔ NaBi ↔ Na 3 Bi) during the discharge/charge processes, associated with two voltage plateaus. As for the intercalation/deintercalation mechanism proposed for nanostructured Bi anodes in SIBs, we rationalize the reason why only the Bi phase is detected in the discharged/charged samples under ex-situ XRD conditions through addressing the stability issue of the Na-Bi system (NaBi and Na 3 Bi). [ABSTRACT FROM AUTHOR]

Ag-Zn alloys are identified as highly active and selective electrocatalysts for CO2 reduction reaction (CO2RR), while how the phase composition of the alloy affects the catalytic performances has not been systematically studied yet. In this study, we fabricated a series of Ag-Zn alloy catalysts by magnetron co-sputtering and further explored their activity and selectivity towards CO2 electroreduction in an aqueous KHCO3 electrolyte. The different Ag-Zn alloys involve one or more phases of Ag, AgZn, Ag5Zn8, AgZn3, and Zn. For all the catalysts, CO is the main product, likely due to the weak CO binding energy on the catalyst surface. The Ag5Zn8 and AgZn3 catalysts show a higher CO selectivity than that of pure Zn due to the synergistic effect of Ag and Zn, while the pure Ag catalyst exhibits the highest CO selectivity. Zn alloying improves the catalytic activity and reaction kinetics of CO2RR, and the AgZn3 catalyst shows the highest apparent electrocatalytic activity. This work found that the activity and selectivity of CO2RR are highly dependent on the element concentrations and phase compositions, which is inspiring to explore Ag-Zn alloy catalysts with promising CO2RR properties. [ABSTRACT FROM AUTHOR]

Low electronic conductivity and drastic volume change during cycling of transition metal oxides, as anodes for lithium ion batteries (LIBs), lead to rapid capacity decay and poor structural stability. Herein, nanostructured NiCo 2 O 4 anchored on carbon sheets was synthesized by a facile hydrothermal method with following thermal treatment. The wrinkled carbon substrate in the composite derives from the carbonization of pomelo peels, which can be mass-produced for the large-scale application. This composite shows mesoporous structures with high specific surface areas and intimate NiCo 2 O 4 /carbon interfaces, which favors the alleviation of the volume expansion/shrink during charging/discharging process and improves the electron/mass transport, enhancing the capability and stability for LIBs. This composite delivers a high reversible capacity of 473.7 mA h g−1 after 210 cycles at a current density of 500 mA g−1. A long cycle life of up to 1100 cycles at 2000 mA g−1 is achieved with the retention capacity of 363 mA h g−1. The electrode also exhibits excellent rate capability and can regain its original capacities as reversing to the low current densities. This work highlights the biomass-derived carbon-supported metal oxides as an environmentally friendly and economic strategy for advanced LIBs. • Carbon substrate as buffer for anode materials can be derived from pomelo peels. • Cycling stability of NiCo 2 O 4 is improved by depositing it on carbon substrate. • Faster Li+ diffusion coefficients are obtained with the existence of carbon. [ABSTRACT FROM AUTHOR]

Alloying Ni with Pd lowers the overpotential of benzaldehyde hydrogenation and obtains a reaction rate 20 times higher than that of Ni at 0.1 V vs. RHE, which is ascribed to the lower binding energy of benzaldehyde on the metal surface revealed by the in-situ IR study. [Display omitted] • Nanoporous nanowire NiPd alloys were synthesized using a dealloying method. • Alloying Ni and Pd lowers the overpotential of ECH of benzaldehyde. • The activity of NiPd alloy is comparable with Pd. • In-situ IR study reveals that Pd tunes the binding strength of adsorbed benzaldehyde. Ni is one of the most promising catalysts in aldehydes hydrogenation, although the high overpotential and low Faradaic efficiency limit its electrocatalytic performances. Here we introduce an effective and facile alloying strategy to tune the electronic structure of Ni. We demonstrate that alloying Pd to Ni can significantly boost the electrocatalytic performances of benzaldehyde hydrogenation and lower the overpotential to the level of pure Pd. Pd introduction enhances the electrocatalytic hydrogenation process over hydrogen evolution reaction (HER), and results in an increased Faradaic efficiency. The npnw-Ni 82 Pd 18 catalyst shows the optimal atomic ratio of Ni and Pd among the explored catalysts, and achieved a turnover frequency (TOF) value of 1387 mol mol metal -1h-1 at -0.1 V vs. reversible hydrogen electrode (RHE), higher than that of npnw-Ni (60 mol mol metal -1h-1) and comparable to np-Pd (1306 mol mol metal -1h-1) under the same reaction conditions. In-situ surface-enhanced infrared absorption spectroscopy study reveals that the electronic interactions between Ni and Pd would activate the adsorbed benzaldehyde, and therefore result in an enhanced activity in benzaldehyde hydrogenation. [ABSTRACT FROM AUTHOR]

A room-temperature Ag 3 Ga-mediated liquid EGaSn anode with improved wettability for advanced Mg ion batteries. [Display omitted] • The room-temperature Ag 3 Ga-mediated liquid EGaSn anode was simply prepared for MIBs. • Ag 3 Ga can improve the wettability of EGaSn on the substrate and provide capacity. • ssm-Ag 3 Ga-EGaSn shows superior electrochemical performance in half and full cells. • Reaction mechanism of the Ag 3 Ga-mediated liquid EGaSn anode was unveiled. Liquid metals with a self-healing property can address the passivation issue of Mg metal and the huge volume variation problem of solid alloy-type anodes in rechargeable magnesium ion batteries (MIBs). Liquid Ga-based anodes show great potentials in MIBs, however, being operated at room temperature is a great challenge. Herein, a novel strategy is proposed to enhance the room-temperature Mg storage performance of liquid eutectic GaSn (EGaSn) alloy through constructing a bifunctional intermetallic compound (Ag 3 Ga) layer on the current collector. This Ag 3 Ga layer could greatly improve the wettability of EGaSn on the substrate in the electrolyte environment. Moreover, operando X-ray diffraction confirms that Ag 3 Ga could participate the reversible alloying/dealloying reactions during the discharge/charge processes and thus provide an extra capacity. Eventually, the Ag 3 Ga-mediated EGaSn anode exhibits outstanding electrochemical performance towards Mg storage in both half and full cells at room temperature (∼24 and 21 °C), as benchmarked with state-of-the-art anodes in MIBs. Specially, the MIBs could be stably cycled up to 600 cycles in the half cell configuration, and 100 cycles in the full cell assembly. This work provides useful information on the development of advanced anodes for MIBs. [ABSTRACT FROM AUTHOR]

Transition metal oxalate materials have shown huge competitive advantages for applications in supercapacitors. Herein, nanostructured cobalt oxalate supported on cobalt foils has been facilely fabricated by anodization, and could directly serve as additive/binder-free electrodes for supercapacitors. The as-prepared cobalt oxalate electrodes present superior specific capacitance of 1269 F g −1 at the current density of 6 A g −1 in the galvanostatic charge/discharge test. Moreover, the retained capacitance is as high as 87.2% as the current density increases from 6 A g −1 to 30 A g −1 . More importantly, the specific capacitance of cobalt oxalate retains 91.9% even after super-long cycling of 100,000 cycles. In addition, an asymmetric supercapacitor assembled with cobalt oxalate (positive electrode) and activated carbon (negative electrode) demonstrates excellent capacitive performance with high energy density and power density. [ABSTRACT FROM AUTHOR]

A self-healing room-temperature liquid eutectic GaSn anode with improved wettability for advanced Mg ion batteries. [Display omitted] • ∙ Self-healing room-temperature liquid EGaSn anodes were simply prepared for MIBs. • ∙ The wettability of liquid EGaSn on ssm-CuGa 2 substrate was significantly improved. • ∙ The ssm-CuGa 2 -EGaSn shows greatly enhanced cycling stability and rate performance. • ∙ Reaction mechanism and self-healing feature of liquid EGaSn anodes were unveiled. Using alloy-type anodes offers an effective method to address the incompatibility issue between Mg metal anodes and conventional electrolytes and also facilitates the development of high performance magnesium ion batteries (MIBs). But the huge volume variations of alloy-type anodes during cycling impair the electrochemical performance of MIBs. Herein, a liquid eutectic GaSn (EGaSn) electrode with a low melting point (20.5 °C) and self-healing property was fabricated through simply painting onto stainless steel mesh (ssm). But the ssm-EGaSn electrode shows unsatisfactory electrochemical performance due to poor wettability of liquid EGaSn on ssm. To overcome this problem, a CuGa 2 layer was constructed to enhance the wettability of liquid EGaSn on the ssm substrate. The modified liquid EGaSn electrode delivers much better electrochemical performance (specific capacity, cycling stability and rate performance) either at ∼ 38 or 28 °C. Furthermore, operando X-ray diffraction and ex situ scanning electron microscopy were conducted to reveal the Mg storage mechanism and self-healing feature of the liquid EGaSn electrode. Noticeably, the liquid EGaSn electrode displays well compatibility with simple Mg salt electrolytes like Mg(TFSI) 2 and the full cell could display stable electrochemical behavior over dozens of cycles. [ABSTRACT FROM AUTHOR]

Nanoporous tungsten (np-W) synthesized by a facile dealloying strategy was utilized as the host to accommodate tellurium (Te) for Li-Te batteries. The np-W supported Te (np-W-Te) cathode exhibits an excellent specific volumetric capacity of 1168 mA h cm−3 after 30 cycles, a good cycling performance of 200 cycles with a coulombic efficiency over 98.9%, and fast rate capabilities of 1612 mA h cm−3 at a current density of 50 mA g−1 and 774 mA h cm−3 at 800 mA g−1. The excellent performance of the np-W-Te cathode is attributed to the highly dispersed Te impregnated in the np-W host with rich porosity, high conductivity and superior stability. The mechanism investigation by in situ Raman and ex situ XRD techniques demonstrates the reversible transformation between Li and Li 2 Te during the charge/discharge processes. This study highlights the nanoporous metal as a promising host to confine Te for Li-Te batteries. Nanoporous tungsten synthesized by dealloying acted as the host to accommodate Te for Li-Te batteries. ga1 • The as-dealloyed nanoporous W hosted Te as the cathode for Li-Te batteries. • The cathode exhibited high specific capacity, good cycling and rate performances. • The reversible conversion between Te and Li 2 Te is the mechanism for the battery. [ABSTRACT FROM AUTHOR]