Hong Yuan

Bio: Hong Yuan is an academic researcher from Beijing Institute of Technology. The author has contributed to research in topics: Lithium & Battery (electricity). The author has an hindex of 22, co-authored 53 publications receiving 2319 citations. Previous affiliations of Hong Yuan include Tsinghua University.

Lithium-Sulfur Batteries under Lean Electrolyte Conditions: Challenges and Opportunities.

Abstract: The development of energy-storage devices has received increasing attention as a transformative technology to realize a low-carbon economy and sustainable energy supply. Lithium-sulfur (Li-S) batteries are considered to be one of the most promising next-generation energy-storage devices due to their ultrahigh energy density. Despite the extraordinary progress in the last few years, the actual energy density of Li-S batteries is still far from satisfactory to meet the demand for practical applications. Considering the sulfur electrochemistry is highly dependent on solid-liquid-solid multi-phase conversion, the electrolyte amount plays a primary role in the practical performances of Li-S cells. Therefore, a lean electrolyte volume with low electrolyte/sulfur ratio is essential for practical Li-S batteries, yet under these conditions it is highly challenging to achieve acceptable electrochemical performances regarding sulfur kinetics, discharge capacity, Coulombic efficiency, and cycling stability especially for high-sulfur-loading cathodes. In this Review, the impact of the electrolyte/sulfur ratio on the actual energy density and the economic cost of Li-S batteries is addressed. Challenges and recent progress are presented in terms of the sulfur electrochemical processes: the dissolution-precipitation conversion and the solid-solid multi-phasic transition. Finally, prospects of future lean-electrolyte Li-S battery design and engineering are discussed.

Controlling Dendrite Growth in Solid-State Electrolytes

Abstract: Solid-state electrolytes (SSEs) are widely considered as an “enabler” to inhibit dendrite growth of lithium-metal anodes for high-energy and highly safe next-generation batteries. However, recent s...

Guidelines and trends for next-generation rechargeable lithium and lithium-ion batteries.

Abstract: Commercial lithium-ion (Li-ion) batteries suffer from low energy density and do not meet the growing demands of the energy storage market. Therefore, building next-generation rechargeable Li and Li-ion batteries with higher energy densities, better safety characteristics, lower cost and longer cycle life is of outmost importance. To achieve smaller and lighter next-generation rechargeable Li and Li-ion batteries that can outperform commercial Li-ion batteries, several new energy storage chemistries are being extensively studied. In this review, we summarize the current trends and provide guidelines towards achieving this goal, by addressing batteries using high-voltage cathodes, metal fluoride electrodes, chalcogen electrodes, Li metal anodes, high-capacity anodes as well as useful electrolyte solutions. We discuss the choice of active materials, practically achievable energy densities and challenges faced by the respective battery systems. Furthermore, strategies to overcome remaining challenges for achieving energy characteristics are addressed in the hope of providing a useful and balanced assessment of current status and perspectives of rechargeable Li and Li-ion batteries.

High-Power Lithium Batteries from Functionalized Carbon Nanotube Electrodes

Abstract: 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.