Review—Multifunctional Materials for Enhanced Li-Ion Batteries Durability: A Brief Review of Practical Options

Abstract

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...

Fast Lithium Ion Conduction in Lithium Phosphidoaluminates

“…Theh igh structural diversity of the Li atoms including disorder and split positions reflects the possibility of high lithium ion mobility.L i-P distances in the tetrahedral voids range from 2.50(1) to 2.73(1) ,a nd in the octahedral voids they range from 2.56(1) to 3.46 (1) .T he bond lengths are similar to those in other ternary phases containing Li and P, such as Li 8 SiP 4 ,Li 2 SiP 2 ,L i 10 SiP 2 ,a nd Li 3 Si 3 P 7 . [47,60] According to the valence rules,L i 9 AlP 4 is an electronprecise compound and can be described as (Li + ) 9 [AlP 4 ] 9À , with formally two negative charges for the Pa toms and one negative charge for the Al atom, balanced by nine Li + ions.…”

“…Thed evelopment of advanced energy-storage technologies plays ak ey role in realizing electric vehicles. [1][2][3][4] Nextgeneration high-energy-density storage systems require low flammability,good electrochemical stability,and fast charging times.L i-ion batteries based on organic electrolytes hinder the commercialization of long-range electric vehicles.A llsolid-state batteries (ASSBs) are promising candidates to overcome safety concerns of currently used Li-ion batteries with flammable organic liquid electrolytes. [5][6][7][8] Replacing the organic liquid electrolyte by an inorganic solid-state electrolyte (SSE), ASSBs offer high energy and power density, mechanical stability,and safety benefits.…”

A SEI Modeling Approach Distinguishing between Capacity and Power Fade

“…Hence, the reduction of ε s, pos corresponds to the LAM in our model. Acid attack by HF is one of the dominating causes for active material dissolution at the cathode 50,69,70 and is implemented as an irreversible kinetics expression in the positive electrode domain. As HF evolution is promoted at potentials above 4.0 V, 69 this potential is used as the equilibrium potential E Eq,diss .…”

Editors' Choice—The Effectiveness of Multifunctional Li-Ion Battery Separators past Their Saturation with Transition Metal Ions

“…Our data suggest that the improved surface films created during the cell formation process are the root cause for reduced parasitic reactions and the immunity of the cell performance to the contamination of the negative electrodes by manganese ions after the saturation of the MFSs with transition metal ions. The benefits for cell performance enabled by MFSs result from the combined effects of Mn trapping, reduced loss of electroactive Li + ions (as deduced from the reduced LMO lattice shrinking, [19][20][21] see also Figure S6), and from to the deposition of Na + ions onto the graphite electrode, which was shown to be beneficial for its SEI. 28 Improvements in Li-ion cells' performance were demonstrated with a commercial ion-exchange resin embedded into home-made separators having physical characteristics similar to those of commercial LIB separators.…”