Bottom-Up Magnesium Deposition Induced by Paper-Based Triple-Gradient Scaffolds toward Flexible Magnesium Metal Batteries

Sustainable release of LiNO3 in carbonate electrolytes for stable lithium metal anodes

LiNO3 is recognized as an effective additive, forming a dense, nitrogen-rich solid electrolyte interphase (SEI) on lithium's surface, which safeguards it from parasitic reactions. However, its use is limited due to the poor solubility in carbonate electrolytes. Herein, we introduce a bilayer separator designed to release LiNO3 sustainably. This continual release not only alters the chemistry of the SEI but also replenishes the additives that are depleted during battery cycling, thereby enhancing the durability of the modified interphase. This strategy effectively curtails Li dendrite formation, significantly enhancing the longevity of Li|LiFePO4 batteries, evidenced by an impressive 85% capacity retention after 800 cycles. This research offers a compelling remedy to the longstanding challenge of incorporating LiNO3 in carbonate electrolytes.

Stabilizing Lithium-Metal Host Anodes by Covalently Binding MgF2 Nanodots to Honeycomb Carbon Nanofibers

Constructing lithiophilic carbon hosts has been regarded as an effective strategy for inhibiting Li dendrite formation and mitigating the volume expansion of Li metal anodes. However, the limitation of lithiophilic carbon hosts by conventional surface decoration methods over long-term cycling hinders their practical application. In this work, a robust host composed of ultrafine MgF2 nanodots covalently bonded to honeycomb carbon nanofibers (MgF2/HCNFs) is created through an in situ solid-state reaction. The composite exhibits ultralight weight, excellent lithiophilicity, and structural stability, contributing to a significantly enhanced energy efficiency and lifespan of the battery. Specifically, the strong covalent bond not only prevents MgF2 nanodots from migrating and aggregating but also enhances the binding energy between Mg and Li during the molten Li infusion process. This allows for the effective and stable regulation of repeated Li plating/stripping. As a result, the MgF2/HCNF-Li electrode delivers a high Coulombic efficiency of 97% after 200 cycles, cycling stably for more than 2000 h. Furthermore, the full cells with a LiFePO4 cathode achieve a capacity retention of 85% after 500 cycles at 0.5C. This work provides a strategy to guide dendrite-free Li deposition patterns toward the development of high-performance Li metal batteries.