Gradient Structure Design of a Floatable Host for Preferential Lithium Deposition
Qiuchan Cai, Xianying Qin, Kui Lin, Zijin Yang, Xia Hu, Tong Li, Feiyu Kang, Baohua Li
Abstract
Herein, a novel sandwichlike host with expandable accommodation and gradient characteristics of lithiophilicity and conductivity is prepared by constructing a reduced graphene oxide (rGO)/SiO2/rGO intercalated structure on the basis of electrospraying and coating an additional PVDF-HFP layer on the top surface. This gradient host electrode enables preferential, ordered, and uniform Li deposition in the SiO2-embedded interlayer space. The dendrite growth and isolated Li are suppressed by the combined rGO/PVDF-HFP layer with robust, flexible, and floatable features, which could function as an artificial solid–electrolyte interphase to impede reckless electrolyte infiltration, homogenize the Li ion flux distribution, and build a stable electrochemical interface. The designed electrodes could be stably cycled with a high capacity of 5 mAh cm–2 and give rise to a high average Coulombic efficiency (CE) of 99.14%. Furthermore, the derived full cells can deliver an average CE of 99.87% in 300 cycles with a capacity retention of 90.22% and successfully operate under lean electrolyte conditions.