There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Li-ion batteries have transformed portable electronics and will play a key role in the electrification of transport. However, the highest energy storage possible for Li-ion batteries is insufficient for the long-term needs of society, for example, extended-range electric vehicles. To go beyond the horizon of Li-ion batteries is a formidable challenge; there are few options. Here we consider two: Li-air (O(2)) and Li-S. The energy that can be stored in Li-air (based on aqueous or non-aqueous electrolytes) and Li-S cells is compared with Li-ion; the operation of the cells is discussed, as are the significant hurdles that will have to be overcome if such batteries are to succeed. Fundamental scientific advances in understanding the reactions occurring in the cells as well as new materials are key to overcoming these obstacles. The potential benefits of Li-air and Li-S justify the continued research effort that will be needed.

Li-O2 and Li-S batteries with high energy storage.

TiO2 photocatalysis and related surface phenomena

Lithium-ion batteries have had a profound impact on our daily life, but inherent limitations make it difficult for Li-ion chemistries to meet the growing demands for portable electronics, electric vehicles and grid-scale energy storage. Therefore, chemistries beyond Li-ion are currently being investigated and need to be made viable for commercial applications. The use of metallic Li is one of the most favoured choices for next-generation Li batteries, especially Li-S and Li-air systems. After falling into oblivion for several decades because of safety concerns, metallic Li is now ready for a revival, thanks to the development of investigative tools and nanotechnology-based solutions. In this Review, we first summarize the current understanding on Li anodes, then highlight the recent key progress in materials design and advanced characterization techniques, and finally discuss the opportunities and possible directions for future development of Li anodes in applications.

Reviving the lithium metal anode for high-energy batteries

The lithium metal battery is strongly considered to be one of the most promising candidates for high-energy-density energy storage devices in our modern and technology-based society. However, uncontrollable lithium dendrite growth induces poor cycling efficiency and severe safety concerns, dragging lithium metal batteries out of practical applications. This review presents a comprehensive overview of the lithium metal anode and its dendritic lithium growth. First, the working principles and technical challenges of a lithium metal anode are underscored. Specific attention is paid to the mechanistic understandings and quantitative models for solid electrolyte interphase (SEI) formation, lithium dendrite nucleation, and growth. On the basis of previous theoretical understanding and analysis, recently proposed strategies to suppress dendrite growth of lithium metal anode and some other metal anodes are reviewed. A section dedicated to the potential of full-cell lithium metal batteries for practical applicatio...

Toward Safe Lithium Metal Anode in Rechargeable Batteries: A Review.

New, Highly Ion-Conductive Crystals Precipitated from Li2S–P2S5 Glasses

A novel route to form superhydrophobic−superhydrophilic micropatterned coating film has been developed UV light was irradiated on the superhydrophobic coating film which consists of three layers, a flowerlike Al2O3 gel film, a very thin TiO2 gel layer, and a FAS layer, to cleave the fluoroalkyl chain in FAS selectively, and well-defined superhydrophobic and superhydrophilic regions were formed

Superhydrophobic−Superhydrophilic Micropatterning on Flowerlike Alumina Coating Film by the Sol−Gel Method

High lithium ion conducting glass-ceramics in the system Li2S–P2S5

All-solid-state Li/S batteries with highly conductive glass–ceramic electrolytes

Alumina thin films with a roughness of 20 to 50 nm were formed by immersing porous alumina gel films prepared by the sol-gel method in boiling water. When hydrolyzed fluoroalkyltrimethoxysilane was coated on the alumina films, the contact angle for water was increased with an increase of immersion time, and immersion for 30 s was long enough to give super-water-repellency and high transparency; the contact angle for water of the film was 165° and the transmittance for the visible light was higher than 92%. It was found that the surface of the alumina gel films immersed in boiling water consisted of boehmite crystals. It was shown that the existence of air in the hydrophobic pores on the surface caused the super-water-repellency.

Kiyoharu Tadanaga

Papers

New, Highly Ion-Conductive Crystals Precipitated from Li2S–P2S5 Glasses

Superhydrophobic−Superhydrophilic Micropatterning on Flowerlike Alumina Coating Film by the Sol−Gel Method

High lithium ion conducting glass-ceramics in the system Li2S–P2S5

All-solid-state Li/S batteries with highly conductive glass–ceramic electrolytes

Formation Process of Super-Water-Repellent Al2O3 Coating Films with High Transparency by the Sol–Gel Method