Highly efficient ionic transport networks by one-dimensional HNTs to enhance the performance of composite solid electrolytes for lithium metal batteries

Composite solid electrolytes (CSEs) have both high safety and long cycle life, and are the key materials for the next-generation lithium batteries. However, due to low ionic conductivity and poor interfacial compatibility, their practical application in high-energy-density lithium metal batteries is limited. This work introduces one-dimensional (1D) halloysite nano tube (HNT) into a Polyvinylidene fluoride (PVDF)/ lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)/ Li 6.85 La 2.95 Yb 0.05 Zr 1.85 Ta 0.15 O 12 (LLYZTO) CSE (PLLH- x ), and investigates its effect on the structure, mechanical and electrochemical properties. HNTs nanotubes with external negative and internal positive electrical polarity, can construct continuous lithium ions (Li⁺) transport pathways between LLYZTO particles and delay the diffusion of TFSI - anion. The obtained PLLH-7 electrolyte has an ionic conductivity of 8.52 × 10 -4 S cm -1 , a Li⁺ transference number of 0.80 and a mechanical strength of 12.3 MPa. The Li symmetric cells assembled based on it exhibit long cycle stability for 2400 h and realize effective inhibition of lithium dendrites. The Li/PLLH-7/LiFePO 4 (LFP) battery still has a discharge specific capacity of 131.6 mA h g -1 after 350 cycles at 0.2 C, with the Coulombic efficiency of 95.4%, showing excellent cycle stability. The Li/PLLH-7/LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) battery also exhibits excellent high-voltage and high-rate tolerance, with the specific capacity maintaining at 124.1 mA h g -1 after 500 cycles at 1 C. This study provides an effective method to improve the ionic conductivity, mechanical and electrochemical property of PVDF composite electrolyte.