Surface‐Confined Disordered Hydrogen Bonds Enable Efficient Lithium Transport in All‐Solid‐State PEO‐Based Lithium Battery

Polyethylene oxide (PEO)-based electrolytes are essential to advance all-solid-state lithium batteries (ASSLBs) with high safety/energy density due to their inherent flexibility and scalability. However, the inefficient Li⁺ transport in PEO often leads to poor rate performance and diminished stability of the ASSLBs. The regulation of intermolecular H-bonds is regarded as one of the most effective approaches to enable efficient Li⁺ transport, while the practical performances are hindered by the electrochemical instability of free H-bond donors and the constrained mobility of highly ordered H-bonding structures. To overcome these challenges, we develop a surface-confined disordered H-bond system with stable donor-acceptor interactions to construct a loosened chain segments/ions arrangement in the bulk phase of PEO-based electrolytes, realizing the crystallization inhibition of PEO, weak coordination of Li⁺ and entrapment of anions, which are conducive to efficient Li⁺ transport and stable Li⁺ deposition. The rationally designed LiFePO₄-based ASSLB demonstrates a long cycle-life of over 400 cycles at 1.0 C and 65 °C with a capacity retention rate of 87.5 %, surpassing most of the currently reported polymer-based ASSLBs. This work highlights the importance of confined disordered H-bonds on Li⁺ transport in an all-solid-state battery system, paving the way for the future design of polymer-based ASSLBs.