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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 LiFePO4 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 LiNi0.8Co0.1Mn0.1O2-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.

To construct highly stable Lithium (Li) metal batteries (LMBs), a polyurethane-LiF based artificial protective membrane (APM) is evenly coated onto LM anodes by a facile solution casting method. Owning to the good ionic conductivity and mechanical properties, APM acts as a physical protective isolation layer between electrolytes and LM to alleviate electrolyte decomposition and suppress Li dendrites. By applying the APM modification, the electrochemical performance of LM is dramatically improved. The Li | APM-Cu half-cell stably circulates 120 cycles with a high Coulombic efficiency of above 90% at a current density of 1 mA cm−2 and an area capacity of 1 mAh cm−2. The APM-Li based symmetric cell presents an ultralong life span of over 1500 h at an area capacity of 1 mAh cm−2and a current density of 0.5 mA cm−2. In full-cell tests, the APM-Li | LiFePO4 configuration maintains a high specific capacity of 120.4 mAh g−1 after 600 cycles with a superior capacity retention of 97.3% at 2C. Additionally, the extraordinary cyclability of APM-Li | Li4Ti5O12 full-cell demonstrates the effectiveness and versatility of APM. The scanning electron microscopy studies confirm the APM's suppression effects of Li dendrites. Therefore, this work provides a promising and affordable APM modification strategy to redeem highly stable LMBs.

The spinel lithium titanate (Li4Ti5O12, LTO) has attracted special attention for its low cost, stable structure and little safety issue. However, LTO displays a low electronic conductivity, which seriously impedes its practical applications at remarkable rate capability. Herein, to improve the electrochemical properties of LTO, this research constructed a novel composite anode by mixing the GaSn liquid metal (LM) nanoparticles with LTO. The composite anode’s phase structure and morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical data indicate that LM-LTO electrode delivers a better rate capability (52% retention from 10 mA/g to 500 mA/g) as well as long cyclic stability (76% retention after 1000 cycles at 200 mA/g). Therefore, this work opens a new avenue for fabricating better rate performance and safer lithium ions battery.