Transition-Metal Dissolution from NMC-Family Oxides: A Case Study

Abstract

positive electrodes with 2,3-butanedione and with tetrabutyl ammonium bifluoride as model leaching agents. In the bifluoride trials, it was found that [Ni] in the leachate was proportional to X Co (X Ni ) 3 , where X M is the ideal stoichiometry in the bulk oxide, and inversely proportional to (X Mn ) 2 ; [Mn] to X Co (X Ni ); and [Co] to X Co . The relationships between metal concentrations and stoichiometry may indicate that nickel, as a next-nearest neighbor on the positive electrode surface, can make dissolution more favorable in some instances.

A Comprehensive Understanding of the Aging Effects of Extreme Fast Charging on High Ni NMC Cathode

“…The closely packed electrochemical cathode aging data in Figure 3a,c is another indication that the extent of TM dissolution in Figure 6 is not strongly contributing to cathode aging. The 9C low‐voltage conditions re‐confirm the general conclusion for NMC [ 46,47 ] that constraining the charge voltage can reduce the overall TM dissolution. The 9C low‐voltage data extends that general conclusion to aggressively charging conditions up to 9C.…”

“…This order of total TM dissolution is in‐line with earlier observations for NMC811 and can be attributed to the relative composition of the three metals and the respective solvation states at elevated oxidation states. [ 45,46 ] For the 4.1 V charge cutoffs, Co and Mn dissolution remain comparable irrespective of C‐rate, as shown in Figure 6b,c. An increase in Ni dissolution is more distinct for the different C‐rate conditions with a 4.1 V charge cutoff between 425 and 600 cycles, which was also observed in earlier studies with non‐XFC conditions; [ 45 ] however, it remains within the error bound except for the 6C‐4.1 V condition, which shows a slightly lower Ni dissolution.…”

A Review of Performance Attenuation and Mitigation Strategies of Lithium‐Ion Batteries

“…Meanwhile, the electrolyte decomposition is an exothermic reaction along with gas release, which will increase the risk of battery explosion. [ 75 ]…”

Identification of LiPF6Decomposition Products in Li‐Ion Batteries with Endogenous Vanadyl Sensors Using Pulse Electron Paramagnetic Resonance and Density Functional Theory

“…To some degree, this effect has been observed for all common cathode materials. [13][14][15] The capacity is reduced because the transition metal is the primary redox center, facilitating lithium intercalation into the material. In addition, as the capacity of the anode is usually a few percentage larger than the cathode to prevent lithium plating at high states of charge, the amount of cathode active material is the capacity bottleneck.…”