Effectively suppressing dissolution of manganese from spinel lithium manganate via a nanoscale surface-doping approach

Abstract

The capacity fade of lithium manganate-based cells is associated with the dissolution of Mn from cathode/electrolyte interface due to the disproportionation reaction of Mn(III), and the subsequent deposition of Mn(II) on the anode. Suppressing the dissolution of Mn from the cathode is critical to reducing capacity fade of LiMn 2 O 4 -based cells. Here we report a nanoscale surface-doping approach that minimizes Mn dissolution from lithium manganate. This approach exploits advantages of both bulk doping and surface-coating methods by stabilizing surface crystal structure of lithium manganate through cationic doping while maintaining bulk lithium manganate structure, and protecting bulk lithium manganate from electrolyte corrosion while maintaining ion and charge transport channels on the surface through the electrochemically active doping layer. Consequently, the surface-doped lithium manganate demonstrates enhanced electrochemical performance. This study provides encouraging evidence that surface doping could be a promising alternative to improve the cycling performance of lithium-ion batteries.

Development of Pyridine-Boron Trifluoride Electrolyte Additives for Lithium-Ion Batteries

“…[8][9] Several methods have been reported to suppress manganese dissolution and hence improve battery performance. [10][11] Among these methods, incorporating additives in the electrolyte is easy and can also be effective. [12][13] Vinyl pyridines reported by Komaba et al for carbon/LiMn 2 O 4 cells and Schiff bases patented by ATL company for graphite/NMC cells appeared to be effective for suppressing manganese dissolution.…”

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

“…14,26 Among the several proposed mechanisms for transition metal (TM) ion dissolution in Li-ion cells, direct acid attack on positive active materials ranks most prominently. 14,15,40 Reduction of the TM ions dissolution by acid attack necessitates the use HF scavenging materials. A chemically active separator filled with a TM chelating material traps the TM ions dissolved from the positive electrode and prevents their migration to and deposition at the negative electrodes.…”

“…For example, the Mn dissolution rate from LMO is greater at high potentials (above 4 V vs. Li/Li + ) than at lower potentials (below 4 V vs. Li/Li + ), a fact which is inconsistent with the disproportionation concept, since the fraction of Mn 4+ cations in the LMO lattice increases with increasing potential. 13,17 While a very large number of studies in the literature report a variety of results on the oxidation state of Mn species in the negative or positive electrodes of cycled LMO-graphite cells, 11,[18][19][20][21] Mitigation measures for Mn dissolution.-Several mitigation measures for the dissolution of Mn ions and its consequences were proposed in the literature over the past two decades: electrolyte optimization by a judicious choice of additives; [26][27][28][29][30][31][32][33] elemental substitutions in the LMO lattice, 7,13,17,34,35 in order to increase the average oxidation state of the Mn ions; surface coatings on the active material powder or electrodes, in order to avoid direct contacts between electrode and electrolyte solution, and thus prevent HF and other acid attack on the active material; [36][37][38][39][40][41][42] chemically active binders; [43][44][45][46][47][48][49][50] an inorganic Mn ions scavenging barrier layer such as lithium titanate 51 or a solid Li-ion conducting and Mn ions blocking membrane 52 placed in the inter-electrode space; and the utilization of chemically activ...…”

“…[36][37][38][39][40][41][42] The role of the coating is to prevent direct contact between the active material particles and the electrolyte solution, and thus eliminate or at least impede HF and other acid species' attack on LMO. Besides preventing acid attack, surface oxide coatings may also impart structural stability to the spinel through the formation of solid solution layers.…”

Phase and composition controllable synthesis of cobalt manganese spinel nanoparticles towards efficient oxygen electrocatalysis

“…Spinels are traditionally synthesized through solid-state methods involving grinding and firing the mixtures of the corresponding metal oxides, nitrates or carbonates56, which require elevated temperature and prolonged time to overcome the reaction energy barriers7. The prepared spinels often show irregular shape, large particle size and low surface area, seriously affecting their physicochemical properties.…”