Integrated anode with 3D electron/ion conductive network for stable lithium metal batteries

Abstract

Lithium metal anode has attracted increasing attention due to its ultra-high theoretical specific capacity and low redox potential. However, the severe interface problems caused by the parasitic reactions at the anode/separator interface greatly hinder its applications. Herein we design a 3D lithium−boron (LiB) fiber integrated lithium anode with polypropylene separator through the interfacial adhesive strategy with poly(vinylidene fluoride-co-hexafluoropropylene)-based polymer electrolyte. The 3D Li/LiB anode after chemical etching can increase the exchange current density to 36.8 mA cm−2, which is about 14 times the value of the pristine anode with 2.6 mA cm−2. Meanwhile, the poly(vinylidene fluoride-co-hexafluoropropylene)-based polymer electrolyte ensures high ionic conductivity and interfacial stability. Thus, the integrated anode with 3D electron/ion conductive network can guide Li deposition away from the unsafe anode/separator interface, and directly suppress the growth of lithium dendrites. As a result, the integrated anode with LiNi0.83Mn0.06Co0.11O2 cathode exhibits an excellent discharge capacity of 168.3 mAh g −1 at a high current density of 5 C. Besides, the rigid LiB skeleton coupling with flexible PVDF-HFP-based polymer electrolyte can effectively prevent the pulverization of lithium anode during long-term cycling, showing superior cycling stability of 1000 cycles at 1 C with a capacity retention of 76 %. This work provides a promising integrated anode for stable lithium metal batteries without lithium dendrite growth.