Hierarchically porous N-doped carbon derived from biomass as oxygen reduction electrocatalyst for high-performance Al–air battery

Developing large-scale and highly efficient oxygen reduction reaction(ORR)catalysts acts a vital role in realizing wide application of metal–air batteries.Here,we propose a gas-foaming strategy to fabricate sustainable and 3D hierarchically porous N-doped carbon with high specific surface area and abundant defects sites derived from biomass.The obtained catalyst exhibits prominent ORR property with higher half-wave potential(0.861 V)and slightly lower kinetic current density(32.44 m A cm^-2),compared to Pt/C(0.856 V and 43.61 m A cm^-1).Furthermore,employing it as catalyst of air cathode,the Al–air battery delivers remarkable discharge performance with excellent power density of 401 m W cm^-2,distinguished energy density of 2453.4 Wh kg^-1 and extremely high open-circuit voltage of 1.85 V among the reported metal–air batteries in the literatures.This gas-foaming strategy for full utilization of biomass affords a chance to explore scalable advanced catalysts in metal–air battery.     

MOF-derived Co-MOF,O-doped carbon as trifunctional electrocatalysts to enable highly efficient Zn-air batteries and water-splitting

Development of high-efficiency non-noble electrocatalysts for oxygen reduction reaction(ORR),oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)is urgently needed for high-performance Zn-air batteries and overall water splitting.Here,a facile strategy to synthesize novel Co-MOF,O-doped carbon(Co-MOF-T)based on Zn,Co-doped glucosamine and ZIF-8 by pyrolysis at temperature T was demonstrated.The prepared Co-MOF-800 showed a superior oxygen reduction reaction(ORR)activity comparable to that of commercial Pt/C catalyst.In addition,this catalyst shows great potential in the overall water splitting due to the excellent oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)activities.Based on the trifunctional activity,the primary Zn-air batteries using a Co-MOF-800 air electrode achieved a high open-circuit voltage of 1.38 V,a specific capacity of 671.6 mAh g^-1 Zn,and a prominent peak power density of 144 mW cm^-2.Also,the rechargeable Zn-air batteries based on CoMOF-800 air electrode could be smoothly run for 510 cycles with a low voltage gap of 0.58 V.Finally,the trifunctional Co-MOF-800 catalyst was applied to boost the electrochemical water splitting,demonstrating its promising potential as a green energy material for practical applications.     

Ethylene sulfite based electrolyte for non-aqueous lithium oxygen batteries

Non-aqueous lithium–oxygen(Li–O_2) batteries have been considered as the superior energy storage system due to their high-energy density, however, some challenges limit the practical application of Li–O_2 batteries. One of them is the lack of stable electrolyte. In this communication, a novel electrolyte with ethylene sulfite(ES) used as solvent for Li–O_2 batteries was reported. ES solvent showed low volatility and high electrochemical stability. Without a catalyst in the air-electrode of Li–O_2 batteries, the batteries showed high specific capacity, good round-trip efficiency and cycling stability.     

Mitigating side reaction for high capacity retention in lithium-sulfur batteries

Li–S batteries have shown great potential as secondary energy batteries. However, the side reaction between Li anodes and polysulfides seriously limited their practical application. Herein, the artificial protective film, which is consisted of Li-Nafion and TiO₂, was designed and successfully prepared to achieve a corrosion-resistant Li anode in Li-S battery. In the composite protective film, the Li-Nafion could efficiently prevent the contact between Li anodes and polysulfides, and t...     

Three-in-one LaNiO3 functionalized separator boosting electrochemical stability and redox kinetics for high-performance Li-S battery

The lithium-sulfur(Li-S) battery, as one of the energy storage devices, has been in the limelight due to its high theoretical energy density. However, the poor redox kinetics and the ‘‘shuttle effect” of polysulfides severely restrict the use of Li-S batteries in practical applications. Herein, a novel bimetallic LaNiO₃functional material with high electrical conductivity and catalytic property is prepared to act as a high-efficiency polysulfide shuttling stopper. The three LaNiO_...     

Anode surface engineering of zinc-ion batteries using tellurium nanobelt as a protective layer for enhancing energy storage performance

Over the years, zinc-ion batteries(ZIBs) have attracted attention as a promising next-generation energy storage technology because of their excellent safety, long cycling performance, eco-friendliness, and high-power density. However, issues, such as the corrosion and dissolution of the Zn anode, limited wettability, and lack of sufficient nucleation sites for Zn plating, have limited their practical application. The introduction of a protective layer comprising of tellurium(Te) nanobelts onto t...     

Revisiting the anodic stability of nickel-cobalt hydroxide/carbon composite electrodes for rechargeable Ni-Zn battery

Aqueous rechargeable Ni-Zn batteries are considered as a new generation of safe and reliable electrochemical energy storage system. However, low electronic conductivity of Ni-based cathodes hinders the practical application of Ni-Zn batteries. This problem can be overcome by compositing the Ni-based cathode with highly conductive carbon substrates. A chemical oxidation pre-treatment is popularly applied to the carbon substrates to increase their hydrophilicity and thus facilitate the growth of a...     

Recent advances of metal phosphides for Li-S chemistry

Li-S batteries have been considered as one of advanced next-generation energy storage systems owing to their remarkable theoretical capacity(1672 m Ah g^-1)and high energy density(2600 Wh kg^-1).However,critical issues,mainly pertaining to lithium polysulfide shuttle and slow sulfur reaction kinetics,have posed a fatal threat to the electrochemical performances of Li-S batteries.The situation is even worse for high sulfur-loaded and flexible cathodes,which are the essential components for practical Li-S batteries.In response,the use of metal compounds as electrocatalysts in Li-S systems have been confirmed as an effective strategy to date.Particularly,recent years have witnessed many progresses in phosphidesoptimized Li-S chemistry.This has been motivated by the superior electron conductivity and high electrocatalytic activity of phosphides.In this tutorial review,we offer a systematic summary of active metal phosphides as promoters for Li-S chemistry,aiming at helping to understanding the working mechanism of phosphide electrocatalysts and guiding the construction of advanced Li-S batteries.     

Synthesis and application of single-atom catalysts in sulfur cathode for high-performance lithium–sulfur batteries

Lithium–sulfur(Li-S) batteries are regarded as one of the most promising energy storage devices because of their low cost, high energy density, and environmental friendliness. However, Li-S batteries suffer from sluggish reaction kinetics and serious “shuttle effect” of lithium polysulfides(LiPSs), which causes rapid decay of battery capacity and prevent their practical application. To address these problems, introducing single-atom catalysts(SACs) is an effective method to improve the electroch...     

Chloride ion battery: A new emerged electrochemical system for next-generation energy storage

In the scope of developing new electrochemical concepts to build batteries with high energy density,chloride ion batteries(CIBs) have emerged as a candidate for the next generation of novel electrochemical energy storage technologies, which show the potential in matching or even surpassing the current lithium metal batteries in terms of energy density, dendrite-free safety, and elimination of the dependence on the strained lithium and cobalt resources. However, the development of CIBs is still a...     

Preface to Special Column on Electrocatalysis

Energy is the most important problem that we are facing.The limited fossil fuel reserves and the air pollution caused by the consuming of fossil fuels force the governments,industries and academia to look for renewable energies and their conversion-storage devices.Some novel concepts based on the electrochemical reactions have been considered as promising solutions to help solve energy problems and improve the quality of our lives.Electrocatalysis plays a critical role in the advanced electrochemical energy systems such as fuell cells,metal-air batteries,and electrolyzers.     

Rational design of porous carbon allotropes as anchoring materials for lithium sulfur batteries

The shuttle effect seriously impedes the development and practical application of lithium sulfur(Li-S)batteries.It is still a long-term challenge to find effective anchoring materials to hinder the shuttle effect of Li-S batteries.Using carbon allotrope as anchoring materials is an effective strategy to alleviate the shuttling effect.However,the influence factors of carbon allotrope on the adsorption performance of LIPSS at the atomic level are not clear,which limits the application of carbon allotrope in Li-S batteries.Herein,using first-principles simulations,a systematical calculation of carbon allotropes with various ring size(6 ≤S≤16) and shape is conducted to understand the adsorption mechanism.The results show that the T-G monolayers with suitable ring structure and high charge transfer can significantly enhance the interaction between the monolayer and LiPSs,allowing them to have high capacity and high coulombic efficiency.Further diffusion studies show that LiPSs on the T-G monolayer have the low diffusion barriers,which ensures the charging and discharging rate of batteries.Our studies could provide material design principles of carbon allotrope monolayers used as anchoring materials of the high performance Li-S batteries.     

A Perspective: the Technical Barriers of Zn Metal Batteries

Energy storage will witness a leap of understanding of new battery chemistries.Considering the safety that cannot be compromised,new aqueous batteries may surface as the solutions to meet the immense market needs,where the growth of renewables is no longer limited by the lack of storage.Aqueous Zn-metal batteries are intriguing candidates to deliver the desirable properties and exhibit competitive levelized energy cost.However,the fact that most commercial Zn batteries are primary batteries states the difficulty of reversibility for the reactions of electrodes in such batteries.This article will highlight the practical needs that guide the development of storage batteries.The causes of irreversibility for both cathode and zinc metal anode are discussed,and the potential solutions for these challenges are summarized.Zn metal batteries may one day address the storage needs,and there exists a vast potential to further improve the properties of reactions in this battery.     

Advances in efficient electrocatalysts based on layered double hydroxides and their derivatives

The explore and development of electrocatalysts have gained significant attention due to their indispensable status in energy storage and conversion systems, such as fuel cells, metal–air batteries and solar water splitting cells. Layered double hydroxides(LDHs) and their derivatives(e.g., transition metal alloys, oxides, sulfides, nitrides and phosphides) have been adopted as catalysts for various electrochemical reactions, such as oxygen reduction, oxygen evolution, hydrogen evolution, and CO_2 reduction, which show excellent activity and remarkable durability in electrocatalytic process. In this review, the synthesis strategies, structural characters and electrochemical performances for the LDHs and their derivatives are described. In addition, we also discussed the effect of electronic and geometry structures to their electrocatalytic activity. The further development of high-performance electrocatalysts based on LDHs and their derivatives is covered by both a short summary and future outlook from the viewpoint of the material design and practical application.     

Hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets as an efficient bifunctional catalyst for Zn–air battery

Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets(Co/N-Pg) is fabricated for Zn–air batteries. A lowcost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn–air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap(0.81 V at 50 mA cm~(-2)) and high peak power density(119 mW cm~(-2)) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn–air battery.     

Post lithium–sulfur battery era:challenges and opportunities towards practical application

Lithium–sulfur(Li–S) batteries have been regarded as a promising next-generation energy storage system owing to the high theoretical energy density and natural abundance of sulfur. Abundant fundamental researches have pushed the flourishing development on electrochemical behaviors in recent 20 years. It is time to evolve into post-Li–S battery era with the pursuit towards practical application. During the landmark leap, numerous new challenges appear under harsh conditions, such as high sulfur l...     

Important roles of graphene edges in carbon-based energy storage devices

Nanostructured carbon materials, including carbon nanotubes, graphene and nanoporous carbon, show promise for expanding renewable energy. In particular, the configuration and electronic properties of graphene edges in relation with their electrochemical activity have become a major issue in carbon-based energy storage devices. Here, we review recent results concerning the important roles of graphene edges as the gateway for lithium ion intercalation in the anode of lithium-ion batteries, as promoters of high capacitance in carbon-based supercapacitors, and as anchoring sites for Pt nanoparticles in fuel cells. We envisage that the controlled synthesis of a specific, clean, and stable edge configuration could be achieved to maximize the electrochemical performance of nanostructured carbon-based energy storage devices.     

Themed Issue on Advanced Battery Material Chemistry

The researches on material chemistry promote the flourishing development of advanced rechargeablebattery since the practical applications of lithium-ion batteries in the 1900s.Rational design andfunctionalization of advanced materials render fruitful trends in improving the energy density and lifespanof rechargeable batteries.We herein organize this themed issue on Advanced Battery Material Chemistry topresent their recent progresses as well as prospect their further advances and developments in variousapplications ranging from portable electronic devices to large-scale energy storage systems.     

Metal-organic frameworks based single-atom catalysts for advanced fuel cells and rechargeable batteries

The next-generation energy storage systems such as fuel cells, metal-air batteries, and alkali metal(Li,Na)-chalcogen(S, Se) batteries have received increasing attention owing to their high energy density and low cost. However, one of the main obstacles of these systems is the poor reaction kinetics in the involved chemical reactions. Therefore, it is essential to incorporate suitable and efficient catalysts into the cell. These years, single-atom catalysts(SACs) are emerging as a frontier in ca...     

Non-stoichiometric CoS1.097 nanoparticles prepared from CoAl-layered double hydroxide and MOF template as cathode materials for aluminum-ion batteries

As a main force in the energy evolution,lithium-ion batteries(LIBs)have been extensively studied in recent decades and are widely used in energy storage and portable electronic products as a result of their advantages of high working voltage and long cycle performance.