Pd-integrated nanostructured electrode-boosted direct ammonia borane fuel cells with power density of over 700 mW cm−2

Direct ammonia borane fuel cells (DABFCs) offer promising portable energy solutions but face limitations from sluggish anodic kinetics and electrode degradation. This study introduces a three-dimensional hierarchical Pd-integrated nanostructured electrode (Pd-INE) synergizing nanostructuring with interfacial engineering. Vertically oriented Pd-decorated nanosheets are electronically coupled to nickel foam (NF) via Ni(OH) 2 , maximizing active site accessibility and structural stability. Density functional theory (DFT) confirms 1.18 e − transfer from Pd to Ni(OH) 2 generates electron-deficient Pd sites that weaken NH 3 BH 3 adsorption (ΔE ads  = −0.92 eV) while enabling bifunctional catalysis: Pd activates B H bonds and Ni(OH) 2 -derived interfacial hydroxyls drive B O formation. Pd-INE demonstrates superior ammonia borane oxidation activity versus conventional polymer-bound Pd/NF while achieving a record peak power density of 724.1 mW cm −2 at 80 °C in DABFC operation, 2.3 times higher than both Pd/NF (321.2 mW cm −2 ) and prior benchmarks (315 mW cm −2 ). This enhancement stems from vertical nanosheets enhancing mass/charge transport and DFT-validated electronic interactions optimizing intermediate adsorption energies. The anode exhibits exceptional durability with 35 μV h −1 voltage decay over 40 h, outperforming polymer-bound anodes by 150-fold. This work establishes an ionomer-free anode paradigm resolving activity-durability trade-offs in direct liquid fuel cells through atomically tailored bifunctional interfaces.