Amino functionlized halloysite nanotubes optimizing composite solid electrolyte for advanced solid-state lithium metal batteries

Battery systems are experiencing unprecedented growth due to the unprecedented application of new energy vehicles. However, most materials used in batteries are produced along with high energy consumption, inevitable pollution or other problems. In contrast with these materials, natural mineral resources have their own attractive advantages such as their unique structures formed in long process. Based on the situation and broad prospects of natural minerals utilized in practical solid-state lithium metal batteries (SSLMBs), this research focuses on polydopamine (PDA) modified halloysite nanotubes (HNTs) as the filler to co mpose a composite solid electrolyte (CSE), in which there are still bis-(trifluoromethane)sulfonimide (LiTFSI) as a lithium salt and poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) as a polymer. As the one-dimensional (1D) materials, HNTs can provide mechanical strength and flame retardant while PDA adhered to HNTs can improve the dispersion of filler in the electrolyte, capture dissolved transition metal (TM) ions from cathode, and facilitate Li + ion transport. The fabricated CSE in this study exhibits a high Li + transference number of 0.48, a great ionic conductivity of 0.24 mS cm −1 , a broader electrochemical window of 4.8 V, and good cycling performance on Li||Li symmetrical cell for over 1000 h and LiNi 0.5 Co 0.2 Mn 0.3 O 2 ||Li (NCM523||Li) battery, with the capacity retention rates of 90% after 200 cycles at 0.5 C and 83.9% after 400 cycles at 1 C, respectively. Meanwhile, LiFePO 4 ||PHHP||Li (LFP||PHHP||Li) battery also provides a capacity retention rate of 89.6% and an average CE of 99.5% after 100 cycles at 0.5 C. This study introduces a new option for natural mineral materials to be applied to high-performance SSLMBs.