The Promise of Environmentally Benign Redox Flow Batteries by Molecular Engineering

Green redox flow batteries: The development of environmentally benign sustainable energy storage systems is eagerly awaited. Organic and organometallic-based electroactive materials are green alternatives to realize this goal. Using rational molecular design and function-oriented organic synthesis, a general design principle is presented to build high-performance green redox flow batteries.

A Hydrogen-Evolving Hybrid-Electrolyte Battery with Electrochemical/Photoelectrochemical Charging from Water Oxidation

Decoupled hydrogen and oxygen production were successfully embedded into an aqueous dual-electrolyte (acid-base) battery for simultaneous energy storage and conversion. A three-electrode configuration was adopted, involving an electrocatalytic hydrogen-evolving electrode as cathode, an alkaline battery-type or capacitor-type anode as shuttle, and a charging-assisting electrode for electro-/photoelectrochemically catalyzing water oxidation. The conceptual battery not only synergistically outputs electricity and chemical fuels with tremendous specific energy and power densities, but also supports various approaches to be charged by pure or solar-assisted electricity.

Conformal, Nanoscale ZnO Surface Modification of Garnet-Based Solid-State Electrolyte for Lithium Metal Anodes

Solid-state electrolytes are known for nonflammability, dendrite blocking, and stability over large potential windows. Garnet-based solid-state electrolytes have attracted much attention for their high ionic conductivities and stability with lithium metal anodes. However, high-interface resistance with lithium anodes hinders their application to lithium metal batteries. Here, we demonstrate an ultrathin, conformal ZnO surface coating by atomic layer deposition for improved wettability of garnet solid-state electrolytes to molten lithium that significantly decreases the interface resistance to as low as ∼20 Ω·cm². The ZnO coating demonstrates a high reactivity with lithium metal, which is systematically characterized. As a proof-of-concept, we successfully infiltrated lithium metal into porous garnet electrolyte, which can potentially serve as a self-supported lithium metal composite anode having both high ionic and electrical conductivity for solid-state lithium metal batteries. The facile surface treatment method offers a simple strategy to solve the interface problem in solid-state lithium metal batteries with garnet solid electrolytes.

Progress and directions in low-cost redox-flow batteries for large-scale energy storage

Compared to lithium-ion batteries, redox-flow batteries have attracted widespread attention for long-duration, large-scale energy-storage applications. This review focuses on current and future directions to address one of the most significant challenges in energy storage: reducing the cost of redox-flow battery systems. A high priority is developing aqueous systems with low-cost materials and high-solubility redox chemistries. Highly water-soluble inorganic redox couples are important for developing technologies that can provide high energy densities and low-cost storage. There is also great potential to rationally design organic redox molecules and fine-tune their properties for both aqueous and non-aqueous systems. While many new concepts begin to blur the boundary between traditional batteries and redox-flow batteries, breakthroughs in identifying/developing membranes and separators and in controlling side reactions on electrode surfaces also are needed.

Energy storage applications of biomass-derived carbon materials: batteries and supercapacitors

Recent advances in the application of biomass-derived carbon materials in batteries and supercapacitors.

Design and synthesis of a free-standing carbon nano-fibrous web electrode with ultra large pores for high-performance vanadium flow batteries

A highly porously free-standing nano fibrous web electrode has been designed and fabricated for VFB through a novel horizontally-opposed blending electrospinning method in this study.

Electrocatalysis for the oxygen evolution reaction: recent development and future perspectives

We review the fundamental aspects of metal oxides, metal chalcogenides and metal pnictides as effective electrocatalysts for the oxygen evolution reaction.

Redox-Flow Batteries: From Metals to Organic Redox-Active Materials

Research on redox-flow batteries (RFBs) is currently experiencing a significant upturn, stimulated by the growing need to store increasing quantities of sustainably generated electrical energy. RFBs are promising candidates for the creation of smart grids, particularly when combined with photovoltaics and wind farms. To achieve the goal of "green", safe, and cost-efficient energy storage, research has shifted from metal-based materials to organic active materials in recent years. This Review presents an overview of various flow-battery systems. Relevant studies concerning their history are discussed as well as their development over the last few years from the classical inorganic, to organic/inorganic, to RFBs with organic redox-active cathode and anode materials. Available technologies are analyzed in terms of their technical, economic, and environmental aspects; the advantages and limitations of these systems are also discussed. Further technological challenges and prospective research possibilities are highlighted.

Fluorine-Doped Antiperovskite Electrolyte for All-Solid-State Lithium-Ion Batteries

A fluorine-doped antiperovskite Li-ion conductor Li2 (OH)X (X=Cl, Br) is shown to be a promising candidate for a solid electrolyte in an all-solid-state Li-ion rechargeable battery. Substitution of F(-) for OH(-) transforms orthorhombic Li2 OHCl to a room-temperature cubic phase, which shows electrochemical stability to 9 V versus Li(+) /Li and two orders of magnitude higher Li-ion conductivity than that of orthorhombic Li2 OHCl. An all-solid-state Li/LiFePO4 with F-doped Li2 OHCl as the solid electrolyte showed good cyclability and a high coulombic efficiency over 40 charge/discharge cycles.

Li-Ion Conduction and Stability of Perovskite Li3/8Sr7/16Hf1/4Ta3/4O3

A solid Li-ion conductor with a high room temperature Li-ion conductivity and small interfacial resistance is required for its application in next-generation Li-ion batteries. Here, we prepared a cubic perovskite-related oxide with the general formula Li3/8Sr7/16Hf1/4Ta3/4O3 (LSHT) by a conventional solid-state reaction method, which was studied by X-ray diffraction, electrochemical impedance spectroscopy, and (7)Li MAS NMR. Li3/8Sr7/16Hf1/4Ta3/4O3 has a high Li-ion conductivity of 3.8 × 10(-4) S cm(-1) at 25 °C and a low activation energy of 0.36 eV in the temperature range 298-430 K. It exhibits both high stability and small interfacial resistance with commercial organic liquid electrolytes, which makes it promising as a separator in Li-ion batteries.

Design, synthesis and applications of core-shell, hollow core, and nanorattle multifunctional nanostructures

With the evolution of nanoscience and nanotechnology, studies have been focused on manipulating nanoparticle properties through the control of their size, composition, and morphology. As nanomaterial research has progressed, the foremost focus has gradually shifted from synthesis, morphology control, and characterization of properties to the investigation of function and the utility of integrating these materials and chemical sciences with the physical, biological, and medical fields, which therefore necessitates the development of novel materials that are capable of performing multiple tasks and functions. The construction of multifunctional nanomaterials that integrate two or more functions into a single geometry has been achieved through the surface-coating technique, which created a new class of substances designated as core-shell nanoparticles. Core-shell materials have growing and expanding applications due to the multifunctionality that is achieved through the formation of multiple shells as well as the manipulation of core/shell materials. Moreover, core removal from core-shell-based structures offers excellent opportunities to construct multifunctional hollow core architectures that possess huge storage capacities, low densities, and tunable optical properties. Furthermore, the fabrication of nanomaterials that have the combined properties of a core-shell structure with that of a hollow one has resulted in the creation of a new and important class of substances, known as the rattle core-shell nanoparticles, or nanorattles. The design strategies of these new multifunctional nanostructures (core-shell, hollow core, and nanorattle) are discussed in the first part of this review. In the second part, different synthesis and fabrication approaches for multifunctional core-shell, hollow core-shell and rattle core-shell architectures are highlighted. Finally, in the last part of the article, the versatile and diverse applications of these nanoarchitectures in catalysis, energy storage, sensing, and biomedicine are presented.

Probing the electrochemical capacitance of MXene nanosheets for high-performance pseudocapacitors

Atomic insight into the interaction between Ti₂CO₂nanosheet cathode and the electrolyte cations, and the calculated pseudocapacitance of Ti₂CO₂nanosheets.