Lithiated halloysite nanotube/cross-linked network polymer composite artificial solid electrolyte interface layer for high-performance lithium metal batteries

• Lithiated halloysite nanotubes and networked polymers are used to prepare a cost-effective artificial composite SEI layer. • This nanocomposite artificial SEI layer exhibits excellent electrochemical and mechanical properties. • The NCL-Li composite anode displays superior Li stripping/platting behavior. • The NCL-Li|NCM811 cells display a good cycling stability and promising safety performance. In lithium metal batteries (LMBs), the instability of the solid electrolyte interface (SEI) induced lithium dendrites and dead lithium frequently causes low cyclability and serious safety issues. Thereby, a highly stable artificial SEI layer with excellent lithium-ion mobility is desirable for dendrite-free lithium metal (LM) anodes. Herein, a novel clay/cross-linked network polymer-based artificial SEI layer (named as NCL) is prepared via compositing lithiated halloysite nanotubes (Li-HNTs) and cross-linked network polymers. The obtained NCL exhibits a promising Li + transference number of 0.39, high ionic conductivity of 6.37 × 10 -4 S cm −1 at 20 °C and superb mechanical performance. Benefiting these advantages, Li + can be uniformly and fast plated/stripped under the protection of NCL, effectively suppressing the formation of lithium dendrites. The NCL-protected LM symmetrical cells can be stably cycled for more than 1000 h and 1100 h at 1 mA cm −2 under cycling capacities of 1 mAh cm −2 and 3 mAh cm −2 , respectively. The NCL-Li|Cu half-cells present dendrite-free and reversible Li deposition with a high Coulombic efficiency of 99% for 170 cycles at 0.5 mA cm −2 . Moreover, the LiFePO 4 full-cell successfully achieves a good capacity of 115 mAh g −1 with a sensational capacity retention of 97.5% over 800 cycles at 2C. Additionally, 300 mAh LiNi 0.8 Co 0.1 Mn 0.1 O 2 -coupled pouch-cells not only can stably circulate more than 50 cycles, but also can reliably function at repetitive mechanical deformation statuses and at different damage conditions. Therefore, this novel hybrid artificial SEI protective layer with desirable properties shed new light on the practical application of high-performance LMBs.