Composite Lithium Metal Anodes with Lithiophilic and Low‐Tortuosity Scaffold Enabling Ultrahigh Currents and Capacities in Carbonate Electrolytes

• Published in: Advanced functional materials Vol. 31; no. 14
• Main Authors: Wu, Jingyi, Rao, Zhixiang, Liu, Xueting, Shen, Yue, Yuan, Lixia, Li, Zhen, Xie, Xiaolin, Huang, Yunhui
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.04.2021
• Subjects: Anodes; dendrite; Dendritic structure; Electrolytes; Electrolytic cells; Flux density; high capacity; high current; Lithium; lithium metal anode; low tortuosity; Materials science; Nanofibers; Nucleation; Plating; Stripping; Titanium dioxide; Tortuosity
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202009961

The practical application of lithium metal anode has been hindered by safety and cyclability issues due to the uncontrollable dendrite growth, especially during fast cycling and deep plating/stripping process. Here, a composite Li metal anode supported by periodic, perpendicular, and lithiophilic TiO2/poly(vinyl pyrrolidone) (PVP) nanofibers via a facial rolling process is reported. TiO2/PVP nanofibers with good Li affinity provide low‐tortuosity and directly inward Li+ transport paths to facilitate Li nucleation and deposition under high areal capacities and current densities. The micrometer‐scale interspaces between TiO2/PVP walls offer enough space to circumvent the huge volume variation and avoid structure collapsing during the repeated deep Li plating/stripping. The unique structure enables stable cycling under ultrahigh currents (12 mA cm−2), and ultra‐deep plating/stripping up to 60 mAh cm−2 with a long cycle life in commercial carbonate electrolytes. The gassing behavior in operating pouch cells is observed using ultrasonic transmission mapping. When paired with LiFePO4 (5 mAh cm−2), sulfur (3 mAh cm−2), and high‐voltage LiNi0.8Co0.1Mn0.1O2 cathodes, the composite Li anodes deliver remarkably improved rate performance and cycling stability, demonstrating that it could be a promising strategy for balancing high‐energy density and high‐power density in Li metal batteries. A multilevel‐structured composite Li anode is developed to greatly lower the risk of internal short‐circuiting caused by dendrite penetration. A high current density of 12 mA cm−2 and ultra‐deep plating/stripping of 60 mAh cm−2 are achieved in the commercial carbonate electrolyte.