The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/aenm.202103045.

Silicon (Si)‐based negative electrodes have attracted much attention to increase the energy density of lithium ion batteries (LIBs) but suffer from severe volume changes, leading to continuous re‐formation of the solid electrolyte interphase and consumption of active lithium. The pre‐lithiation approach with the help of positive electrode additives has emerged as a highly appealing strategy to decrease the loss of active lithium in Si‐based LIB full‐cells and enable their practical implementation. Here, the use of lithium squarate (Li2C4O4) as low‐cost and air‐stable pre‐lithiation additive for a LiNi0.6Mn0.2Co0.2O2 (NMC622)‐based positive electrode is investigated. The effect of additive oxidation on the electrode morphology and cell electrochemical properties is systematically evaluated. An increase in cycle life of NMC622||Si/graphite full‐cells is reported, which grows linearly with the initial amount of Li2C4O4, due to the extra Li+ ions provided by the additive in the first charge. Post mortem investigations of the cathode electrolyte interphase also reveal significant compositional changes and an increased occurrence of carbonates and oxidized carbon species. This study not only demonstrates the advantages of this pre‐lithiation approach but also features potential limitations for its practical application arising from the emerging porosity and gas development during decomposition of the pre‐lithiation additive.

Li‐Ion Batteries In article number 2103045, Aurora Gomez‐Martin, Richard Schmuch, and co‐workers report the effect of Mg substitution on mitigating the structural challenges of Ni‐rich layered oxide cathode materials upon cycling in lithium‐ion batteries. While partial substitution of Mg in Li sites linearly reduces the initial capacities at a given upper cut‐off cell voltage, the attainable cycle life is significantly extended.