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Owing to high specific energy, low cost, and environmental friendliness, lithium–sulfur (Li–S) batteries hold great promise to meet the increasing demand for advanced energy storage beyond portable electronics, and to mitigate environmental problems. However, the application of Li–S batteries is challenged by several obstacles, including their short life and low sulfur utilization, which become more serious when sulfur loading is increased to the practically accepted level above 3–5 mg cm−2. More and more efforts have been made recently to overcome the barriers toward commercially viable Li–S batteries with a high sulfur loading. This review highlights the recent progress in high-sulfur-loading Li–S batteries enabled by hierarchical design principles at multiscale. Particularly, basic insights into the interfacial reactions, strategies for mesoscale assembly, unique architectures, and configurational innovation in the cathode, anode, and separator are under specific concerns. Hierarchy in the multiscale design is proposed to guide the future development of high-sulfur-loading Li–S batteries.

Review on High-Loading and High-Energy Lithium–Sulfur Batteries

Spinels with the formula of AB2O4 (where A and B are metal ions) and the properties of magnetism, optics, electricity, and catalysis have taken significant roles in applications of data storage, biotechnology, electronics, laser, sensor, conversion reaction, and energy storage/conversion, which largely depend on their precise structures and compositions. In this review, various spinels with controlled preparations and their applications in oxygen reduction/evolution reaction (ORR/OER) and beyond are summarized. First, the composition and structure of spinels are introduced. Then, recent advances in the preparation of spinels with solid-, solution-, and vapor-phase methods are summarized, and new methods are particularly highlighted. The physicochemical characteristics of spinels such as their compositions, structures, morphologies, defects, and substrates have been rationally regulated through various approaches. This regulation can yield spinels with improved ORR/OER catalytic activities, which can furth...

Spinels: Controlled Preparation, Oxygen Reduction/Evolution Reaction Application, and Beyond

Energy storage devices that can deliver high powers have many applications, including hybrid vehicles and renewable energy. Much research has focused on increasing the power output of lithium batteries by reducing lithium-ion diffusion distances, but outputs remain far below those of electrochemical capacitors and below the levels required for many applications. Here, we report an alternative approach based on the redox reactions of functional groups on the surfaces of carbon nanotubes. Layer-by-layer techniques are used to assemble an electrode that consists of additive-free, densely packed and functionalized multiwalled carbon nanotubes. The electrode, which is several micrometres thick, can store lithium up to a reversible gravimetric capacity of approximately 200 mA h g(-1)(electrode) while also delivering 100 kW kg(electrode)(-1) of power and providing lifetimes in excess of thousands of cycles, both of which are comparable to electrochemical capacitor electrodes. A device using the nanotube electrode as the positive electrode and lithium titanium oxide as a negative electrode had a gravimetric energy approximately 5 times higher than conventional electrochemical capacitors and power delivery approximately 10 times higher than conventional lithium-ion batteries.

High-Power Lithium Batteries from Functionalized Carbon Nanotube Electrodes

Solution combustion is an exciting phenomenon, which involves propagation of self-sustained exothermic reactions along an aqueous or sol–gel media. This process allows for the synthesis of a variety of nanoscale materials, including oxides, metals, alloys, and sulfides. This Review focuses on the analysis of new approaches and results in the field of solution combustion synthesis (SCS) obtained during recent years. Thermodynamics and kinetics of reactive solutions used in different chemical routes are considered, and the role of process parameters is discussed, emphasizing the chemical mechanisms that are responsible for rapid self-sustained combustion reactions. The basic principles for controlling the composition, structure, and nanostructure of SCS products, and routes to regulate the size and morphology of the nanoscale materials are also reviewed. Recently developed systems that lead to the formation of novel materials and unique structures (e.g., thin films and two-dimensional crystals) with unusual...

Solution Combustion Synthesis of Nanoscale Materials

Heteroatom-Doped Mesoporous Hollow Carbon Spheres for Fast Sodium Storage with an Ultralong Cycle Life

The presence of electrocatalysis in lithium-sulfur batteries has been proposed but not yet sufficiently verified. In this study, molybdenum phosphide (MoP) nanoparticles are shown to play a definitive electrocatalytic role for the sulfur cathode working under lean electrolyte conditions featuring a low electrolyte/active material ratio: the overpotentials for the charging and discharging reactions are greatly decreased. As a result, sulfur electrodes containing MoP nanoparticles show faster kinetics and more reversible conversion of sulfur species, leading to improvements in charging/discharging voltage profiles, capacity, rate performance, and cycling stability. Taking advantage of the electrocatalytic properties of MoP, high-performance sulfur electrodes were successfully realized that are steadily cyclable at a high areal capacity of 5.0 mAh cm-2 with a challenging electrolyte/sulfur (E/S) ratio of 4 μLE  mg-1S  .

Electrocatalysis in Lithium Sulfur Batteries under Lean Electrolyte Conditions

A novel sintering method to obtain fully dense gadolinia doped ceria by applying a direct current

Protonic ceramic fuel cells (PCFCs) have interesting potential to efficiently produce electrical power from fuels in a low-temperature range (<650 °C). However, the sluggish activity of the oxygen reduction reaction is one of the greatest obstacles to the development of PCFCs. Single-phase triple-conducting (e−/O2−/H+) oxides are considered to be the most promising candidates for highly active PCFC cathodes because they can extend the electrochemically active sites to the entire cathode surface. Here, A-site deficiency of perovskite is introduced to tune the triple-conducting properties, which can stimulate the generation of oxygen vacancies and increase the oxygen-ion bulk diffusion and proton hydration kinetics. The so-obtained A-site-deficient perovskite oxides, BaxCo0.4Fe0.4Zr0.1Y0.1O3−δ (x = 1, 0.95, 0.9), exhibit area specific resistance values of 1.61, 0.94, and 0.52 Ω cm2 for BaCo0.4Fe0.4Zr0.1Y0.1O3−δ, Ba0.95Co0.4Fe0.4Zr0.1Y0.1O3−δ, and Ba0.9Co0.4Fe0.4Zr0.1Y0.1O3−δ, respectively, at 500 °C in wet air (pH2O = 0.1 atm). Peak power densities of 797.47, 668.64, 548.07, and 376.27 mW cm−2 are obtained from the PCFC with the Ba0.9Co0.4Fe0.4Zr0.1Y0.1O3−δ cathode at 650, 600, 550 and 500 °C, respectively. Such remarkable performance demonstrates that introducing A-site deficiency is an effective strategy to enhance the triple-conducting properties of perovskite oxides for the high-activity cathode of PCFCs.

Tuning the defects of the triple conducting oxide BaCo0.4Fe0.4Zr0.1Y0.1O3−δ perovskite toward enhanced cathode activity of protonic ceramic fuel cells

The application of lithium–sulfur (Li–S) batteries is severely hampered by the shuttle effect and sluggish redox kinetics. Herein, amorphous cobalt phosphide grown on a reduced graphene oxide-multi...

Zhenhua Wang

Papers

Heteroatom-Doped Mesoporous Hollow Carbon Spheres for Fast Sodium Storage with an Ultralong Cycle Life

Electrocatalysis in Lithium Sulfur Batteries under Lean Electrolyte Conditions

A novel sintering method to obtain fully dense gadolinia doped ceria by applying a direct current

Tuning the defects of the triple conducting oxide BaCo0.4Fe0.4Zr0.1Y0.1O3−δ perovskite toward enhanced cathode activity of protonic ceramic fuel cells

Enhancing Polysulfide Confinement and Electrochemical Kinetics by Amorphous Cobalt Phosphide for Highly Efficient Lithium-Sulfur Batteries.