Li-ion battery materials: present and future

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.

Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocat...

Recent Advances in Ultrathin Two-Dimensional Nanomaterials

Energy production and storage technologies have attracted a great deal of attention for day-to-day applications. In recent decades, advances in lithium-ion battery (LIB) technology have improved living conditions around the globe. LIBs are used in most mobile electronic devices as well as in zero-emission electronic vehicles. However, there are increasing concerns regarding load leveling of renewable energy sources and the smart grid as well as the sustainability of lithium sources due to their limited availability and consequent expected price increase. Therefore, whether LIBs alone can satisfy the rising demand for small- and/or mid-to-large-format energy storage applications remains unclear. To mitigate these issues, recent research has focused on alternative energy storage systems. Sodium-ion batteries (SIBs) are considered as the best candidate power sources because sodium is widely available and exhibits similar chemistry to that of LIBs; therefore, SIBs are promising next-generation alternatives. Recently, sodiated layer transition metal oxides, phosphates and organic compounds have been introduced as cathode materials for SIBs. Simultaneously, recent developments have been facilitated by the use of select carbonaceous materials, transition metal oxides (or sulfides), and intermetallic and organic compounds as anodes for SIBs. Apart from electrode materials, suitable electrolytes, additives, and binders are equally important for the development of practical SIBs. Despite developments in electrode materials and other components, there remain several challenges, including cell design and electrode balancing, in the application of sodium ion cells. In this article, we summarize and discuss current research on materials and propose future directions for SIBs. This will provide important insights into scientific and practical issues in the development of SIBs.

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Sodium-ion batteries: present and future

Energy storage technology has received significant attention for portable electronic devices, electric vehicle propulsion, bulk electricity storage at power stations, and load leveling of renewable sources, such as solar energy and wind power. Lithium ion batteries have dominated most of the first two applications. For the last two cases, however, moving beyond lithium batteries to the element that lies below-sodium-is a sensible step that offers sustainability and cost-effectiveness. This requires an evaluation of the science underpinning these devices, including the discovery of new materials, their electrochemistry, and an increased understanding of ion mobility based on computational methods. The Review considers some of the current scientific issues underpinning sodium ion batteries.

The emerging chemistry of sodium ion batteries for electrochemical energy storage.

Graphite, as the most common anode for commercial Li-ion batteries, has been reported to have a very low capacity when used as a Na-ion battery anode. It is well known that electrochemical insertion of Na(+) into graphite is significantly hindered by the insufficient interlayer spacing. Here we report expanded graphite as a Na-ion battery anode. Prepared through a process of oxidation and partial reduction on graphite, expanded graphite has an enlarged interlayer lattice distance of 4.3 A yet retains an analogous long-range-ordered layered structure to graphite. In situ transmission electron microscopy has demonstrated that the Na-ion can be reversibly inserted into and extracted from expanded graphite. Galvanostatic studies show that expanded graphite can deliver a high reversible capacity of 284 mAh g(-1) at a current density of 20 mA g(-1), maintain a capacity of 184 mAh g(-1) at 100 mA g(-1), and retain 73.92% of its capacity after 2,000 cycles.

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Expanded graphite as superior anode for sodium-ion batteries

To simultaneously address the challenges of chemical/physical short circuits and electrode volume variation, we demonstrate a three-dimensional (3D) bilayer garnet solid-state electrolyte framework for advanced Li metal batteries. The dense layer is reduced in thickness to a few microns and still retains good mechanical stability, thereby enabling the safe use of Li metal anodes. The thick porous layer acts as a mechanical support for the thin dense layer which serves as a host for high loading of cathode materials and provides pathways for continuous ion transport. Results show that the integrated sulfur cathode loading can reach >7 mg cm−2 while the proposed hybrid Li–S battery exhibits a high initial coulombic efficiency (>99.8%) and high average coulombic efficiency (>99%) during the subsequent cycles. This electrolyte framework represents a promising strategy to revolutionize Li-metal batteries by transitioning to all-solid-state batteries and can be extended to other cathode materials.

Three-dimensional bilayer garnet solid electrolyte based high energy density lithium metal–sulfur batteries

Sodium ion batteries (SIBs) have been considered as a top alternative to lithium ion batteries due to the earth abundance and low cost of sodium compared with lithium. Among all proposed anode materials for SIBs, red phosphorus (P) is a very promising candidate because it has the highest theoretical capacity (∼2600 mAh/g). In this study, a red P–single-walled carbon nanotube (denoted as red P–SWCNT) composite, in which red P is uniformly distributed between tangled SWCNTs bundles, is fabricated by a modified vaporization-condensation method. Benefiting from the nondestructive preparation process, the highly conductive and mechanically strong SWCNT network is preserved, which enhances the conductivity of the composite and stabilizes the solid electrolyte interphase. As a result, the red P–SWCNT composite presents a high overall sodium storage capacity (∼700 mAh/gcomposite at 50 mA/gcomposite), fast rate capability (∼300 mAh/gcomposite at 2000 mA/gcomposite), and stable long-term cycling performance with 80...

Red Phosphorus–Single-Walled Carbon Nanotube Composite as a Superior Anode for Sodium Ion Batteries

The use of sulfur in the next generation Li-ion batteries is currently precluded by its poor cycling stability caused by irreversible Li 2 S formation and the dissolution of soluble polysulfi des in organic electrolytes that leads to parasitic cell reactions Here, a new C/S cathode material comprising short-chain sulfur species (predominately S 2 ) confi ned in carbonaceous subnanometer and the unique charge mechanism for the subnano-entrapped S 2 cathodes are reported The fi rst charge‐discharge cycle of the C/S cathode in the carbonate electrolyte forms a new type of thiocarbonate-like solid electrolyte interphase (SEI) The SEI coated C/S cathode stably delivers ≈600 mAh g −1 capacity over 4020 cycles (00014% loss cycle −1 ) at ≈100% Coulombic effi ciency Extensive X-ray photoelectron spectroscopy analysis of the discharged cathodes shows a new type of S 2 species and a new carbide-like species simultaneously, and both peaks disappear upon charging These data suggest a new sulfur redox mechanism involving a separated Li + /S 2− ion couple that precludes Li 2 S compound

Yang Wen

Papers

Expanded graphite as superior anode for sodium-ion batteries

Three-dimensional bilayer garnet solid electrolyte based high energy density lithium metal–sulfur batteries

Red Phosphorus–Single-Walled Carbon Nanotube Composite as a Superior Anode for Sodium Ion Batteries

Confined Sulfur in Microporous Carbon Renders Superior Cycling Stability in Li/S Batteries

High-rate lithium cycling in a scalable trilayer Li-garnet-electrolyte architecture