Design considerations and cycling guidance for aluminum foil anodes in lithium-ion rechargeable cells

Al foil is an attractive anode candidate for Li-ion rechargeable batteries, but the systemic problem of fast capacity degradation limits its re-introduction in practical applications. Partial lithiation-delithiation does mitigate the issue to a certain degree, but the cycle life is still tied to the problems associated with the phase transformation between beta-LiAl and alpha-Al. Utilizing the solubility range of beta-LiAl has been proven to be a feasible approach to stabilize the beta-LiAl grown on an Al foil, i.e., the beta-LiAl(Al) anode, but the electrochemically driven ion transport limitations of this electrode remain largely unclear. Herein, we present comprehensive electrochemical analyses of the beta-LiAl(Al) electrode to shed light on its kinetic limitations which have intrinsic links to the electrode thickness and total cell capacity. Results show that the beta-LiAl(Al) electrode can be charged at a C-rate as high as 2.9 C when a proper prelithiation is done for an Al foil. The superior rate capability is suggested to partly originate from the fast lithium diffusion in beta-LiAl: -10(-7) cm(2)center dot s(-1) at room temperature. Furthermore, the cells consisting of beta-LiAl(Al) vs. commercial Li4Ti5O12 exhibit promising cycling performances, even at 10 mA center dot cm(-2), giving 300 cycles with a capacity retention of similar to 80%. With a systematic investigation of the limiting mechanisms focusing on correlating the prelithiation depth and the cycle life, the cyclability of the beta-LiAl(Al) electrode at different current densities (0.5-10 mA center dot cm(-2)) is mapped out, providing comprehensive guidance for the practical utilization of the beta-LiAl(Al) anode in a range of Li-ion cell types, from all-solid-state batteries to hybrid capacitors.

Automated summary

Al foil is an attractive anode candidate for Li-ion rechargeable batteries, but its fast capacity degradation hinders its practical applications. Utilizing the solubility range of beta-LiAl has been proven to be a feasible approach to stabilize the beta-LiAl grown on an Al foil, but the electrochemically driven ion transport limitations of this electrode remain unclear.