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.

Solid-state electrolytes are attracting increasing interest for electrochemical energy storage technologies. In this Review, we provide a background overview and discuss the state of the art, ion-transport mechanisms and fundamental properties of solid-state electrolyte materials of interest for energy storage applications. We focus on recent advances in various classes of battery chemistries and systems that are enabled by solid electrolytes, including all-solid-state lithium-ion batteries and emerging solid-electrolyte lithium batteries that feature cathodes with liquid or gaseous active materials (for example, lithium–air, lithium–sulfur and lithium–bromine systems). A low-cost, safe, aqueous electrochemical energy storage concept with a ‘mediator-ion’ solid electrolyte is also discussed. Advanced battery systems based on solid electrolytes would revitalize the rechargeable battery field because of their safety, excellent stability, long cycle lives and low cost. However, great effort will be needed to implement solid-electrolyte batteries as viable energy storage systems. In this context, we discuss the main issues that must be addressed, such as achieving acceptable ionic conductivity, electrochemical stability and mechanical properties of the solid electrolytes, as well as a compatible electrolyte/electrode interface. This Review details recent advances in battery chemistries and systems enabled by solid electrolytes, including all-solid-state lithium-ion, lithium–air, lithium–sulfur and lithium–bromine batteries, as well as an aqueous battery concept with a mediator-ion solid electrolyte.

Lithium battery chemistries enabled by solid-state electrolytes

Compared with lithium-ion batteries with liquid electrolytes, all-solid-state batteries offer an attractive option owing to their potential in improving the safety and achieving both high power and high energy densities. Despite extensive research efforts, the development of all-solid-state batteries still falls short of expectation largely because of the lack of suitable candidate materials for the electrolyte required for practical applications. Here we report lithium superionic conductors with an exceptionally high conductivity (25 mS cm−1 for Li9.54Si1.74P1.44S11.7Cl0.3), as well as high stability ( ∼0 V versus Li metal for Li9.6P3S12). A fabricated all-solid-state cell based on this lithium conductor is found to have very small internal resistance, especially at 100 ∘C. The cell possesses high specific power that is superior to that of conventional cells with liquid electrolytes. Stable cycling with a high current density of 18 C (charging/discharging in just three minutes; where C is the C-rate) is also demonstrated. The development of all-solid-state batteries requires fast lithium conductors. Here, the authors report a lithium compound, Li9.54Si1.74P1.44S11.7Cl0.3, with an exceptionally high conductivity and demonstrate that all-solid-state batteries based on the compound have high power densities.

High-power all-solid-state batteries using sulfide superionic conductors

Solid-state batteries have recently attracted great interest as potentially safe and stable high-energy storage systems. However, key issues remain unsolved, hindering full-scale commercialization.

A solid future for battery development

Fabrication and electrochemical properties of a LiCoO2 and Li10GeP2S12 composite electrode for use in all-solid-state batteries

The crystal structures of the superionic conductors Li9.81Sn0.81P2.19S12 and Li10.35Si1.35P1.65S12, both having a Li10GeP2S12 (LGPS)-type structure, were determined by neutron diffraction analysis over the temperature range 12–800 K. The maximum entropy method was also employed to clarify the lithium distribution in these materials. The Sn system showed one-dimensional diffusion in the c direction over a wide temperature range, even though the Ge-based system typically exhibits three-dimensional conduction at higher temperatures. The ionic conduction mechanisms of analogous Si, Ge and Sn phases with LGPS-type structures are discussed on the basis of the observed structural parameter changes.

Structure–property relationships in lithium superionic conductors having a Li10GeP2S12-type structure

Fabrication and electrochemical properties of LiMn2O4/SrRuO3 multi-layer epitaxial thin film electrodes

Synthesis, structure, and electrochemical properties of crystalline Li–P–S–O solid electrolytes: Novel lithium-conducting oxysulfides of Li10GeP2S12 family

Composite Sulfur Electrode Prepared by High-Temperature Mechanical Milling for use in an All-Solid-State Lithium–Sulfur Battery with a Li3.25Ge0.25P0.75S4 Electrolyte

Kota Suzuki

Papers

Fabrication and electrochemical properties of a LiCoO2 and Li10GeP2S12 composite electrode for use in all-solid-state batteries

Structure–property relationships in lithium superionic conductors having a Li10GeP2S12-type structure

Fabrication and electrochemical properties of LiMn2O4/SrRuO3 multi-layer epitaxial thin film electrodes

Synthesis, structure, and electrochemical properties of crystalline Li–P–S–O solid electrolytes: Novel lithium-conducting oxysulfides of Li10GeP2S12 family

Composite Sulfur Electrode Prepared by High-Temperature Mechanical Milling for use in an All-Solid-State Lithium–Sulfur Battery with a Li3.25Ge0.25P0.75S4 Electrolyte