Strategic Approaches to the Dendritic Growth and Interfacial Reaction of Lithium Metal Anode

Low-cost silicon cutting waste reused as a high-power-density silicon-based anode

With the rapid development of electric vehicle technology, commercial graphite anodes (theoretical capacity of 372 mA h g-1) of lithium-ion batteries cannot meet the needs for high power density. Silicon has high theoretical capacity (4200 mA h g-1), low working voltage (about 0.4 V vs. Li/Li+), rich resources and environmental friendly nature; hence, it is regarded as a potential negative electrode material. During repeated charging and discharging, silicon particles continuously pulverize, which leads to the volume expansion of electrode materials (up to 400%) and a decrease in conductivity. In this study, high-purity nano-silicon was prepared via a calcination-ball milling-pickling process with low-cost silicon cutting waste (SiCW) as a raw material to meet the needs of lithium-ion batteries for high-purity and nano-scale silicon-based anodes. At the same time, silicon@graphite nanocomposites with different mass ratios were prepared via a low-cost industrialized ball-milling process. The easy intercalation and softness of the graphite layer structure realized the coating and joining of nano-silicon, which improved the conductivity of nano-silicon and restrained the rapid degradation of cycling performance caused by the expansion and pulverization of the silicon-based anode. Adopting low-cost raw materials and industrialization-based preparation processes can effectively control the production cost of silicon-based anode materials and lay a solid foundation for their practicality.

Porous carbon architectures with different dimensionalities for lithium metal storage

Lithium metal batteries have recently gained tremendous attention owing to their high energy capacity compared to other rechargeable batteries. Nevertheless, lithium (Li) dendritic growth causes low Coulombic efficiency, thermal runaway, and safety issues, all of which hinder the practical application of Li metal as an anodic material. In this review, the failure mechanisms of Li metal anode are described according to its infinite volume changes, unstable solid electrolyte interphase, and Li dendritic growth. The fundamental models that describe the Li deposition and dendritic growth, such as the thermodynamic, electrodeposition kinetics, and internal stress models are summarized. From these considerations, porous carbon-based frameworks have emerged as a promising strategy to resolve these issues. Thus, the main principles of utilizing these materials as a Li metal host are discussed. Finally, we also focus on the recent progress on utilizing one-, two-, and three-dimensional carbon-based frameworks and their composites to highlight the future outlook of these materials.