Lithium magnesium silicate nanoparticles with unique cation acceleration channels as Li-ion rectifiers for stabilizing Li metal batteries

Abstract

Lithium metal anodes possessing a high theoretical specific capacity and low redox potential are considered the most promising materials for high-energy-density Li metal batteries (LMBs). However, safety concerns due to the growth of lithium dendrites and short-cycle lifetime issues due to more side reactions have hindered the practical implementation of LMBs. To alleviate the above problems and further improve the safeness and cycling stability of LMBs, a Li-Nafion@Laponite-XLG@PP (LNLX@PP) based functional separator is proposed. The as-optimized functional separator (LNLX-30@PP) not only has high ionic conductivity (8.4 × 10−4 S cm−1), Li+ transfer number (0.8), and high mechanical properties, but also induces the formation of a strong LiF-rich SEI and hinders anionic shuttling through electrostatic shielding effects. As a result, the Li|LNLX-30@PP |Li symmetric cells can stably cycle for 650 h under high current density (2 mA cm−2) and high charge-discharge capacity (4 mA h cm−2). Furthermore, this approach enables more than 1000 cycles at 3 C with high coulomb efficiency of 99.9 % in LFP||Li coin cells and achieve an actual initial energy density of 322 Wh kg−1 and more than 100 stable cycles at 0.2 C in an assembled Li-S pouch cell with S loading of ∼9.3 mg cm−2. This work will inspire the design of hybrid functional separators for advanced Li metal batteries.