Precise regulation of hydrogen bond networks for rapid ion transport in PEO-based composite solid electrolytes

PEO-based composite solid electrolytes (CSEs) hold significant promise for high-energy all-solid-state lithium metal batteries (SSLMBs) due to their excellent processability and enhanced safety. However, the unregulated chemical environment at the organic-inorganic interface could induce the agglomeration of inorganic fillers and hinder interfacial ion transport, thereby deteriorating the overall electrochemical performance of the CSEs. To address these challenges, we pioneered a controllable hydrogen-bonded interfacial layer by incorporating [3-(2-aminoethylamino)-propyl]trimethoxysilane (AEAPTMS)-modified LLZO nanofibers (A@LLZO) into the PEO matrix. By precisely optimizing the mass ratio of AEAPTMS-to-LLZO, the hydrogen bonds between the amino/imino groups in A@LLZO and the ether oxygen groups in PEO can effectively enhance the mobility of PEO chains and modulate the local Li⁺ coordination environment, thereby facilitating the formation of continuous and low-energy-barrier Li⁺ transport pathways. As a result, CSEs achieve a high ionic conductivity of 0.59 mS cm^-1 and a Li⁺ transference number of 0.63. The assembled Li‖LiFePO₄ (LFP) full cell can deliver a stable capacity of 114 mA h g^-1 under 0.5C over 150 cycles at 60 °C. This work highlights the significant potential of precisely regulating hydrogen bond interactions at the organic-inorganic interface to enhance the performance of CSEs, offering valuable guidance for the development of high-performance SSLMBs.