Conductivity and lithiophilicity gradients guide lithium deposition to mitigate short circuits

Abstract

Lithium metal anodes hold great promise to enable high-energy battery systems. However, lithium dendrites at the interface between anode and separator pose risks of short circuits and fire, impeding the safe application. In contrast to conventional approaches of suppressing dendrites, here we show a deposition-regulating strategy by electrically passivating the top of a porous nickel scaffold and chemically activating the bottom of the scaffold to form conductivity/lithiophilicity gradients, whereby lithium is guided to deposit preferentially at the bottom of the anode, safely away from the separator. The resulting lithium anodes significantly reduce the probability of dendrite-induced short circuits. Crucially, excellent properties are also demonstrated at extremely high capacity (up to 40 mAh cm −2 ), high current density, and/or low temperatures (down to −15 °C), which readily induce dendrite shorts in particular. This facile and viable deposition-regulating strategy provides an approach to preferentially deposit lithium in safer positions, enabling a promising anode for next-generation lithium batteries.

Constructing a High‐Strength Solid Electrolyte Layer by In Vivo Alloying with Aluminum for an Ultrahigh‐Rate Lithium Metal Anode

“…However, the introduction of a large amount of inactive material by a complicated fabrication process dramatically reduces the energy density of the battery for practical applications . Besides, Li‐plating tends to occur at the surface/separator interface near the Li anode due to the smaller resistance of electron and ion charge‐transfer at this interface, increasing the possibility of dendrite formation even by this strategy …”

Gradient‐Distributed Nucleation Seeds on Conductive Host for a Dendrite‐Free and High‐Rate Lithium Metal Anode

“…Higher Li‐ion flux at the host surface, which arouse from Li‐ion diffusion resistance in the bulk electrolyte among the 3D hosts, would weaken the effect of the 3D hosts, leading to overlying deposit of lithium and lithium dendrites. Most recently, a 3D polyethylenimine sponge with lithium‐ion affinity to alleviate vertical lithium‐ion concentration was developed by Wang and co‐workers, while conductivity and lithiophilicity gradients were also induced into the 3D host to achieve stable lithium deposition by Zhang and co‐workers . Developing more effective and universal strategies to overcome the uneven lithium deposition in vertical direction caused by Li‐ion concentration gradient is crucial for the application of 3D hosts for LMAs.…”

Constructing Ionic Gradient and Lithiophilic Interphase for High‐Rate Li‐Metal Anode

“…The dendrite growth was generally caused by the nonuniform Li‐deposition, which was related to the applied current density and potential, as well as the local Li‐ion concentration over the anode . The microscopic ionic distribution near the anode significantly affects the sedimentary morphology.…”