Transition metal (TM) ions dissolution from positive electrodes, migration to and deposition on negative electrodes, followed by Mn-catalyzed reactions of solvents and anions, with loss of Li + ions, is a major degradation (DMDCR) mechanism in Li-ion batteries (LIBs) with spinel positive electrode materials. While the details of the DMDCR mechanism are still under debate, it is clear that HF and other acid species' attack is the main cause in solutions with LiPF 6 electrolyte. We first review the work on various mitigation measures for the DMDCR mechanism, now spanning more than two decades. We then discuss recent progress on our understanding of Mn species in electrolyte solutions and the extension of a mitigation measure first proposed by Tarascon and coworkers in 1999, namely chelation of TM cations, to Mn cation trapping, HF scavenging, and alkali metal ions dispensing multi-functional materials. We focus on practicable, drop-in technical solutions, based on placing such materials in the inter-electrode space, with significant benefits for LIBs performance: increased capacity retention during operation at room and above-ambient temperatures as well as robust (both maximally ionically conducting and electronically insulating) solid-electrolyte interfaces, having reduced charge transfer and film resistances at both negative and positive electrodes. We illustrate the multifunctional materials approach with both new and previously published data. We also discuss and offer our evaluation regarding the merits and drawbacks of the various mitigation measures, with an eye for practically relevant technical solutions capable to meet both the performance requirements and cost constraints for commercial LIBs, and end with recommendations for future work. Li-ion batteries (LIBs) dominate the global market for energystorage devices nowadays and are used in a variety of applications, ranging from portable consumer electronics, to electrical grid storage, to load-levelling and electrified vehicles.1 Electrified vehicles are the most demanding among all LIBs applications in terms of both duty cycle and durability, since the batteries are subjected to a wide range of temperatures and charging/discharging rates, while customers expect a 10 years lifetime. Incessant research on various positive and negative active materials resulted in several promising electrode materials with various crystal structures and chemistries being developed over the past decades, such as layered (LiCoO 2 , LiNi 1-x-y Co x Al y O 2 , Ni 1-x-y Co x Mn y O 2 ), spinel (LiMn 2 O 4 , a.k.a. LMO; LNi 0.5 Mn 1.5 O 2 , a.k.a. LNMO), and olivine (LiFePO 4, LiVPO 4 ) for positive, as well as graphite, silicon, silicon-oxide, and lithium titanate for negative electrodes.2 New developments in electrode materials notwithstanding, LIBs for automotive transportation still need considerable improvements in terms of both performance and durability. Among transition metal (TM) oxide cathodes, LiMn 2 O 4 spinel would be most suited for automotive power cells due to i...