Passivation Failure of Al Current Collector in LiPF₆‐Based Electrolytes for Lithium‐Ion Batteries

Abstract

Next-generation Li-ion batteries are being developed with high-voltage cathodes to maximize their energy and power densities. However, the commercialization of high-voltage cathodes has been delayed due to the degradations of active materials and electrolytes in long-term cycling. Recent advances have made significant improvements in these issues; however, the corrosion of Al current collector and its effects on battery performances have not been studied in detail despite its importance. In this study, the compositional and morphological evolutions of the passivation layer formed on Al are examined. The ion fluxes of Al 3+ and F − through the native oxide layer of Al play a critical role in the formation of the passivation film and the inhibition of further corrosion. However, the continuous diffusion of the ions during long-term cycling at elevated temperature deteriorates the passivation ability of the film. An artificial diffusion barrier on the surface of Al effectively suppresses the ion fluxes to enhance the cyclability of LiNi 0.5 Mn 1.5 O 4 . This work contributes to improving the stability of the current collector at high voltages and serves as a benchmark for corrosion studies concerning advanced energy storage devices.

MXene‐Ti3C2 Armored Layer for Aluminum Current Collector Enable Stable High‐Voltage Lithium‐Ion Battery

“…The standard electrode potential of Al (1.364 V versus Li/Li + ) is much lower than the operating voltage of cathode active material, so the anode Al thermodynamically faces electrochemical oxidation, that is, corrosion. [ 9 ] Generally, the corrosion of Al in organic environment is interpreted as the initial dissolution of Al 2 O 3 to generate Al 3+ , and the subsequent formation and desorption of Al‐complexes initiate localized corrosion, especially at high voltage. [ 8 ] Our proposed armored MXene layer provides superior protection on the basis of natural Al 2 O 3 in LiPF 6 ‐carbonates electrolyte, as shown in Figure .…”

“…[4][5][6][7] Unfortunately, there is a bottleneck-the corrosion (anodic dissolution) of traditional cathode current collector still hinders the application of high-voltage LIBs, leading to the increase of internal resistance, the shedding of electrode material, and the rapid decay of capacity. [8,9] Therefore, it is indispensable to improve the corrosion resistance of cathode current collector at high voltage.…”

Bifunctional Alloy/Solid-Electrolyte Interphase Layer for Enhanced Potassium Metal Batteries Via Prepassivation

“…Although these works promote the interfacial contact between K metal and a CC surface, the high reactivity of K metal results in an inefficient plating-stripping process, leading to low Coulombic efficiency (CE) and inferior cyclic performance. Besides, the conventional CCs used in KMBs are also vulnerable to corrosion under long-term cyclic scenes, which aggravates the side reactions and threatens the safety of battery systems. − …”

High energy density Na-metal batteries enabled by a tailored carbonate-based electrolyte

“…Nevertheless, besides the high price, the commonly used sodium bis(fluorosulfonyl)imide (NaFSI) or sodium bis-(trifluoromethane sulphonyl)imide (NaTFSI) would inevitably give rise to corrosion of Al current collectors at high potentials. [19][20][21] Hence, most ether-based electrolytes are still limited to systems operated with low voltages, such as Na||Na 3 V 2 (PO 4 ) 3 and Na||Na 4 Fe 3 (PO 4 ) 2 (P 2 O 7 ), making a compromise in energy density. 19,20,22 Different from the readily oxidizable ethers, conventional carbonates generally possess high anodic limits up to 4.3 V vs. Na + /Na.…”