Work of adhesion guided nucleation control for energy-dense potassium metal batteries

Summary Dendrite suppression remains a key obstacle to practical alkali metal batteries. Conventional substrate engineering emphasizes surface energy to promote uniform nucleation, yet we show that surface energy alone cannot predict or control potassium nucleation, as revealed by comparative studies on gold and copper substrates. Revisiting heterogeneous nucleation theory, we propose the work of adhesion (Wadh) at the nucleus-substrate interface as the key thermodynamic descriptor governing potassium nucleation. Enhancing effective Wadh through substrate nanotexturing lowers the nucleation barrier and achieves uniform potassium deposition. This Wadh-guided strategy effectively suppresses dendrite formation, stabilizes plating/stripping, and markedly improves electrochemical performance. Perylenetetracarboxylic dianhydride (PTCDA, 20 mg cm−2)||K full cells with an areal capacity of 2.7 mAh cm−2 deliver >99.9% Coulombic efficiency and 91.1% capacity retention over 680 cycles (0.013% per-cycle fade) under lean electrolyte (3.58 mL gPTCDA−1). Potassium manganese hexacyanoferrate (K1.97MnFe(CN)6)||K cells also exhibit substantial performance gains, providing a viable route toward dendrite-free alkali metal batteries.