Robust porous artificial layers with boosted lithiophilicity and Li+ diffusion for dendrite-free Li metal anodes

Abstract

Li has been considered to the most prospective anode for Li batteries because of the lowest redox potential and high theoretical capacity. However, the practical application is hindered by uncontrolled dendrite growth. Herein, a robust porous PVDF/MnO2 (RP-PVDF/MnO2) artificial layer is introduced on Li to form RP-PVDF/MnO2@Li anodes. The porous structure can accelerate Li+ transfer kinetics, while the excellent lithiophilicity of the MnO2 guides the uniform Li nucleation. Meanwhile, the robust RP-PVDF/MnO2 films assembled by the PVDF and ultralong MnO2 nanowires deliver a high Young's modulus of 303 MPa, enabling the mechanical integrity of the artificial layers. As a result, the RP-PVDF/MnO2@Li symmetric half-cells demonstrate remarkable stability up to 3200 h at 10 mAh cm−2 and 10 mA cm−2. The RP-PVDF/MnO2@Li||LiFePO4 (LFP) full-cells maintain 83.5 % capacity retention after 1600 cycles at 2C. Even under harsh cycling condition with a LFP loading of 21.0 mg cm−2, electrolyte/capacity (E/C) of 9.0 g Ah−1 and negative/positive (N/P) of 3.0, the RP-PVDF/MnO2@Li||LFP full-cells can deliver 85.4 % capacity retention after 140 cycles. This work illustrates superiority of robust lithiophilic artificial layers with boosted Li+ transfer kinetics for advanced metal batteries.