Utilization of Li-Rich Phases in Aluminum Anodes for Improved Cycling Performance through Strategic Thermal Control

Abstract

Lithium-ion batteries with aluminum anodes had appeared to resolve critical dendrite issues of lithium metal cells in the 1970s. However, the poor cycling performance attributed to aluminum anodes would lead to their obsolescence. In this work, we demonstrate how strategic thermal control in cycling aluminum anodes circumvents the problematic α/β phase transformations that yield poor cycling life. Instead, electrochemical formation of the Li 3 Al 2 and Li 2−x Al phases necessitates temperatures slightly above ambient, as the Li 3 Al 2 and Li 2−x Al phases are key enablers for high capacity and stable cycling. While delivering a competitive capacity level (ca. 1 Ah kg −1 -Al), cycling among those higher-order phases is found to be significantly improved, from several cycles to 100 cycles with ca. 67% capacity retention. Importantly, because modern battery charging is likely to occur above room temperature due to ohmic heating, the thermal conditions explored here are expected to be realized in a variety of applications. Furthermore, we show that elevated temperature is not necessary for aluminum anode delithiation, thus creating additional synergies with many practical scenarios.

Insights into the Sodiation Kinetics of Si and Ge Anodes for Sodium-Ion Batteries

“…Formation of higherordered phases is often observed for alloy anodes in Li-based systems at elevated temperatures, such as Li 22 Sn 5 , 54 and Li 2-x Al. 55 However, due to the amorphous nature of both phases during sodiation, the formation of Na 3 Ge is not detected by XRD, hence, further investigations are required.…”

Lithium aluminum alloy anodes in Li-ion rechargeable batteries: Past developments, recent progress, and future prospects

“…Since the phase transformations involved in this new cycling approach are different from the well-studied α ↔ β ones, the cycling behavior is expected to be also different due to different material properties. The outcome turned out to indeed be true, that the cyclability of β-LiAl ↔ Li 2−x Al is significantly better than that of α ↔ β (figure 17(b)) [118]. Not only does this finding open up opportunities in real applications as the heat generated by ohmic resistance must be dissipated during operation, but also provides new topics to researchers who are interested in Al-based anodes that have greatly improved stability (β-LiAl ↔ Li 2−x Al cycling) and capacity (1986 mAh g −1 Al for Li 2−x Al).…”

Enhancing Durability and Capacity Retention of Ultrafine-Grained Aluminum Foil Anodes in Lithium-Ion Batteries

“…Aluminum has been identified as a potential metallic foil for use as anode in Li-ion batteries. , This interest is driven by its impressive theoretical capacity 2940 mAh/cm 3 and relatively small volume expansion (96%) compared to Si (297%), Sn (250%), and Ge (270%) during reaction with Li ions. , Recently, there have been much research on the development of high-performance Al foil anode. − Li et al insisted that a high-purity Al foil anode prepared through cold rolling mitigated mechanical damage and promoted uniform formation of β-LiAl phase on the surface. Crowley et al observed substantial entrapment of Li atoms within β-LiAl phases in a pure Al foil electrode after the delithiation process and showed that the introduction of Li and Si elements into the Al matrix could reduce this entrapment of Li atoms.…”