Regulating Cathode‐Electrolyte Interphase by Confining Functional Aluminum Compound within Ni‐Rich Cathodes

Abstract

The oxidative capability of Ni4+ and high operation voltage of nickel‐rich LiNi1−x−yCoxMnyO2 (Ni‐rich NCM) cause its continuous and deleterious side reactions with electrolyte and irreversible phase transition, which hinder its industrial application. To mitigate these issues, Al (CF3SO3)3 is proposed as a solid electrolyte additive that can be readily oxidized to regulate the cathode‐electrolyte interphase (CEI) due to the highest occupied molecular orbital‐level of CF3SO3−, meanwhile being confined within the single‐crystalline NCM811. CF3SO3− prior to the electrolyte is oxidized upon increasing voltage to produce sulfur components and involve CEI formation. Concurrently, the released Al3+ ions are combined with reactive oxygen from NCM811 particles and HF from the electrolyte to form Al2O3 and AlF3, respectively. A robust sandwich CEI film containing sulfur and aluminum species is formed, which cannot only prevent decomposition of the electrolyte, but also alleviate the formation of inactive rock‐salt phase on NCM811 surface. Consequently, such CEI leads to high‐performance batteries with a high‐capacity retention of 91.5% after 200 cycles under 0.5 C compared to 72.4% of pristine NCM811. This facile and environmentally benign method provides a new avenue to develop high‐capacity and durable cathodes for lithium‐ion batteries.

Essence of electrochemical prelithiation of the silicon anode: from the interface to the bulk phase

“…Obviously, a significant decrease in the cell polarization was obtained, indicating the fast electrochemical kinetics with prelithiation. 30 More importantly, a significant enhancement in the cycling behavior of the full-cell using the prelithiated Si was observed (see Fig. 1d).…”

Microstructures of layered Ni-rich cathodes for lithium-ion batteries

“…It should be noted that the coating materials listed in the table are usually coated individually on NRLO particle surfaces, while it is possible to coat several materials simultaneously on the particle surface via appropriate design. 136…”

Coating Effect of Various-Phase Alumina Nanoparticles on NCM811 Cathode for Enhancing Electrochemical Performance of Lithium-Ion Batteries

“…Han et al added Al­(CF 3 SO 3 ) 3 to the solid electrolyte and reacted Al 3+ with the active oxygen in LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) to generate Al 2 O 3 , forming a layer of aluminum-containing CEI film. It can effectively alleviate the decomposition of electrolyte and the phase change of NCM and improve the capacitance retention rate of batteries . Yu et al mixed AlF 3 into Al 2 O 3 to explore the effect of films deposited with different mixing ratios on the performance of Li-rich NCM electrodes .…”