The polyamine molten salt was synthesized through a facile one-step polycondensation route and strategically implemented in the construction of binder-free electrodes for both lithium-ion (LIBs) and sodium-ion batteries (SIBs). The intrinsic viscoelastic properties of the polyamine molten salt enable the fabrication of ultrathin, binder-free electrodes that simultaneously ensure efficient electron transport pathways and maintain exceptional interfacial adhesion to current collectors. Notably, the dynamic self-healing capability of this molten salt system confers remarkable tolerance against high-current-induced stress and prolonged charge/discharge cycling. The rationally designed electrode architecture effectively accommodates volume variations during cycling, thereby significantly suppressing capacity fade and improving long-term cycling stability. In LIBs, the polyamine molten salt exhibited an outstanding reversible specific capacity of 633 mAh g−1 at 100 mA g−1, retaining 407 mAh g−1 after 100 cycles at a high current density of 10 A g−1. Density functional theory (DFT) revealed theoretical Li adsorption sites, showing that the polyamine molten salt surface promotes electron attraction and facilitates Li+ adsorption. As an anode material in SIBs, the binder-free electrodes demonstrated a reversible capacity of 269.45 mAh g−1 after 150 cycles at a high current density of 100 mA g−1, highlighting the potential of polyamine molten salt as a high-performance anode material for both LIBs and SIBs.