Di Bao

In Situ Coupling of Strung Co4N and Intertwined N-C Fibers toward Free-Standing Bifunctional Cathode for Robust, Efficient, and Flexible Zn-Air Batteries.

Flexible power sources with high energy density are crucial for the realization of next-generation flexible electronics. Theoretically, rechargeable flexible zinc-air (Zn-air) batteries could provide high specific energy, while their large-scale applications are still greatly hindered by high cost and resources scarcity of noble-metal-based oxygen evolution reaction (OER)/oxygen reduction reaction (ORR) electrocatalysts as well as inferior mechanical properties of the air cathode. Combining metallic Co4N with superior OER activity and Co-N-C with perfect ORR activity on a free-standing and flexible electrode could be a good step for flexible Zn-air batteries, while lots of difficulties need to be overcome. Herein, as a proof-of-concept experiment, we first propose a strategy for in situ coupling of strung Co4N and intertwined N-C fibers, by pyrolyzation of the novel pearl-like ZIF-67/polypyrrole nanofibers network rooted on carbon cloth. Originating from the synergistic effect of Co4N and Co-N-C and the stable 3D interconnected conductive network structure, the obtained free-standing and highly flexible bifunctional oxygen electrode exhibits excellent electrocatalytic activity and stability for both OER and ORR in terms of low overpotential (310 mV at 10 mA cm(-2)) for OER, a positive half-wave potential (0.8 V) for ORR, and a stable current density retention for at least 20 h, and especially, the obtained Zn-air batteries exhibit a low discharge-charge voltage gap (1.09 V at 50 mA cm(-2)) and long cycle life (up to 408 cycles). Furthermore, the perfect bendable and twistable and rechargeable properties of the flexible Zn-air battery particularly make it a potentially power portable and wearable electronic device.

Electrochemical Reduction of N2 under Ambient Conditions for Artificial N2 Fixation and Renewable Energy Storage Using N2 /NH3 Cycle.

Using tetrahexahedral gold nanorods as a heterogeneous electrocatalyst, an electrocatalytic N2 reduction reaction is shown to be possible at room temperature and atmospheric pressure, with a high Faradic efficiency up to 4.02% at -0.2 V vs reversible hydrogen electrode (1.648 µg h-1 cm-2 and 0.102 µg h-1 cm-2 for NH3 and N2 H4 ·H2 O, respectively).

A Biodegradable Polydopamine‐Derived Electrode Material for High‐Capacity and Long‐Life Lithium‐Ion and Sodium‐Ion Batteries

Polydopamine (PDA), which is biodegradable and is derived from naturally occurring products, can be employed as an electrode material, wherein controllable partial oxidization plays a key role in balancing the proportion of redox-active carbonyl groups and the structural stability and conductivity. Unexpectedly, the optimized PDA derivative endows lithium-ion batteries (LIBs) or sodium-ion batteries (SIBs) with superior electrochemical performances, including high capacities (1818u2005mAhu2009g(-1) for LIBs and 500u2005mAhu2009g(-1) for SIBs) and good stable cyclabilities (93u2009% capacity retention after 580 cycles for LIBs; 100u2009% capacity retention after 1024 cycles for SIBs), which are much better than those of their counterparts with conventional binders.

Au Sub‐Nanoclusters on TiO2 toward Highly Efficient and Selective Electrocatalyst for N2 Conversion to NH3 at Ambient Conditions

As the Nuf8fdN bond in N2 is one of the strongest bonds in chemistry, the fixation of N2 to ammonia is a kinetically complex and energetically challenging reaction and, up to now, its synthesis is still heavily relying on energy and capital intensive Haber-Bosch process (150-350 atm, 350-550 °C), wherein the input of H2 and energy are largely derived from fossil fuels and thus result in large amount of CO2 emission. In this paper, it is demonstrated that by using Au sub-nanoclusters (≈0.5 nm ) embedded on TiO2 (Au loading is 1.542 wt%), the electrocatalytic N2 reduction reaction (NRR) is indeed possible at ambient condition. Unexpectedly, NRR with very high and stable production yield (NH3 : 21.4 µg h-1 mg-1cat. , Faradaic efficiency: 8.11%) and good selectivity is achieved at -0.2 V versus RHE, which is much higher than that of the best results for N2 fixation under ambient conditions, and even comparable to the yield and activation energy under high temperatures and/or pressures. As isolated precious metal active centers dispersed onto oxide supports provide a well-defined system, the special structure of atomic Au cluster would promote other important reactions besides NRR for water splitting, fuel cells, and other electrochemical devices.

Decorating Waste Cloth via Industrial Wastewater for Tube‐Type Flexible and Wearable Sodium‐Ion Batteries

To turn waste into treasure, a facile and cost-effective strategy is developed to revive electroless nickel plating wastewater and cotton-textile waste toward a novel electrode substrate. Based on the substrate, a binder-free PB@GO@NTC electrode is obtained, which exhibits superior electrochemical performance. Moreover, for the first time, a novel tube-type flexible and wearable sodium-ion battery is successfully fabricated.

Amorphizing of Au Nanoparticles by CeOx–RGO Hybrid Support towards Highly Efficient Electrocatalyst for N2 Reduction under Ambient Conditions

Ammonia synthesis is one of the most kinetically complex and energetically challenging chemical processes in industry and has used the Harber-Bosch catalyst for over a century, which is processed under both harsh pressure (150-350 atm) and hightemperature (623-823 K), wherein the energy and capital intensive Harber-Bosch process has a huge energy cost accounting for about 1%-3% of humans energy consumption. Therefore, there has been a rough and vigorous exploration to find an environmentally benign alternative process. As the amorphous material is in a metastable state and has many dangling bonds, it is more active than the crystallized one. In this paper, CeOx -induced amorphization of Au nanoparticles anchored on reduced graphite oxide (a-Au/CeOx -RGO) has been achieved by a facile coreduction method under ambient atmosphere. As a proof-of-concept experiment, a-Au/CeOx -RGO hybrid catalyst containing the low noble metal (Au loading is 1.31 wt%) achieves a high Faradaic efficiency (10.10%) and ammonia yield (8.3 μg h-1 mg-1cat. ) at -0.2 V versus RHE, which is significantly higher than that of the crystalline counterpart (c-Au/RGO), and even comparable to the yields and efficiencies under harsh temperatures and/or pressures.

High-Performance Integrated Self-Package Flexible Li–O2 Battery Based on Stable Composite Anode and Flexible Gas Diffusion Layer

With the rising development of flexible and wearable electronics, corresponding flexible energy storage devices with high energy density are required to provide a sustainable energy supply. Theoretically, rechargeable flexible Li-O2 batteries can provide high specific energy density; however, there are only a few reports on the construction of flexible Li-O2 batteries. Conventional flexible Li-O2 batteries possess a loose battery structure, which prevents flexibility and stability. The low mechanical strength of the gas diffusion layer and anode also lead to a flexible Li-O2 battery with poor mechanical properties. All these attributes limit their practical applications. Herein, the authors develop an integrated flexible Li-O2 battery based on a high-fatigue-resistance anode and a novel flexible stretchable gas diffusion layer. Owing to the synergistic effect of the stable electrocatalytic activity and hierarchical 3D interconnected network structure of the free-standing cathode, the obtained flexible Li-O2 batteries exhibit superior electrochemical performance, including a high specific capacity, an excellent rate capability, and exceptional cycle stability. Furthermore, benefitting from the above advantages, the as-fabricated flexible batteries can realize excellent mechanical and electrochemical stability. Even after a thousand cycles of the bending process, the flexible Li-O2 battery can still possess a stable open-circuit voltage, a high specific capacity, and a durable cycle performance.

Three-dimensional interconnected Ni(Fe)O x H y nanosheets on stainless steel mesh as a robust integrated oxygen evolution electrode

The development of an electrocatalyst based on abundant elements for the oxygen evolution reaction (OER) is important for water splitting associated with renewable energy sources. In this study, we develop an interconnected Ni(Fe)OxHy nanosheet array on a stainless steel mesh (SSNNi) as an integrated OER electrode, without using any polymer binder. Benefiting from the well-defined three-dimensional (3D) architecture with highly exposed surface area, intimate contact between the active species and conductive substrate improved electron and mass transport capacity, facilitated electrolyte penetration, and improved mechanical stability. The SSNNi electrode also has excellent OER performance, including low overpotential, a small Tafel slope, and long-term durability in the alkaline electrolyte, making it one of the most promising OER electrodes developed.

Composition-tunable synthesis of “clean” syngas via a one-step synthesis of metal-free pyridinic-N-enriched self-supported CNTs: the synergy of electrocatalyst pyrolysis temperature and potential

Exploring efficient and environmentally friendly ways for producing clean syngas is of great significance for realizing an artificial carbon cycle associated with clean and renewable energy. Herein, as a proof-of-concept experiment, we controllably synthesized syngas via electroreduction of CO2 using an integrated 3D electrode as the catalyst. An efficient electrode was synthesized in only one step and immediately used for electroreduction of CO2 to CO with a low overpotential. Moreover, pyridinic-N predominated in the synthesized N-CNTs, followed by graphitic-N, both of which were demonstrated to supply the active nitrogen defects for the CO2 conversion. Impressively, by tuning the pyrolysis temperature or applied potential, we were able to easily tailor the H2/CO ratio in the clean syngas products in a large range between 1u2006:u20063 and 3u2006:u20061. This ability to tailor the H2/CO ratio has important applications in industrial production.