Die entscheidende Rolle von lokalen Ladungsfluktuationen beim Wachstum von Dendriten auf Lithium‐Elektroden

Alloy-Type Anodes for High-Performance Rechargeable Batteries

Alloy-type anodes are one of the most promising classes of next-generation anode materials due to their ultrahigh theoretical capacity (2-10 times that of graphite). However, current alloy-type anodes have several limitations: huge volume expansion, high tendency to fracture and disintegrate, an unstable solid-electrolyte interphase (SEI) layer, and low Coulombic efficiency. Efforts to overcome these challenges are ongoing. This Review details recent progress in the research of batteries based on alloy-type anodes and discusses the direction of their future development. We conclude that improvements in structural design, the introduction of a protective interface, and the selection of suitable electrolytes are the most effective ways to improve the performance of alloy-type anodes. Furthermore, future studies should direct more attention toward analyzing their synergistic promoting effect.

First-Principles Studies on the Atomistic Properties of Metallic Magnesium as Anode Material in Magnesium-Ion Batteries

Rechargeable magnesium-ion batteries (MIBs) are a promising alternative to commercial lithium-ion batteries (LIBs). They are safer to handle, environmentally more friendly, and provide a five-time higher volumetric capacity (3832 mAh cm^-3 ) than commercialized LIBs. However, the formation of a passivation layer on metallic Mg electrodes is still a major challenge towards their commercialization. Using density functional theory (DFT), the atomistic properties of metallic magnesium, mainly well-selected self-diffusion processes on perfect and imperfect Mg surfaces were investigated to better understand the initial surface growth phenomena. Subsequently, rate constants and activation temperatures of crucial diffusion processes on Mg(0001) and Mg(10 1 ‾ 1) were determined, providing preliminary insights into the surface kinetics of metallic Mg electrodes. The obtained DFT results provide a data set for parametrizing a force field for metallic Mg or performing kinetic Monte-Carlo simulations.

Modification of Nitrate Ion Enables Stable Solid Electrolyte Interphase in Lithium Metal Batteries

The lifespan of high-energy-density lithium metal batteries (LMBs) is hindered by heterogeneous solid electrolyte interphase (SEI). The rational design of electrolytes is strongly considered to obtain uniform SEI in working batteries. Herein, a modification of nitrate ion (NO₃ ^- ) is proposed and validated to improve the homogeneity of the SEI in practical LMBs. NO₃ ^- is connected to an ether-based moiety to form isosorbide dinitrate (ISDN) to break the resonance structure of NO₃ ^- and improve the reducibility. The decomposition of non-resonant -NO₃ in ISDN enriches SEI with abundant LiN_x O_y and induces uniform lithium deposition. Lithium-sulfur batteries with ISDN additives deliver a capacity retention of 83.7 % for 100 cycles compared with rapid decay with LiNO₃ after 55 cycles. Moreover, lithium-sulfur pouch cells with ISDN additives provide a specific energy of 319 Wh kg^-1 and undergo 20 cycles. This work provides a realistic reference in designing additives to modify the SEI for stabilizing LMBs.