A flexible and potassiphilic porous interconnected mediator for dendrite-free and stable potassium metal anodes

Uncontrollable dendrite growth caused by uneven surface potential distribution and inevitable volume changes during K platting/stripping processes is a huge challenge currently facing the field of potassium metal anodes. Herein, an integrated dendrite-free potassium metal anode is designed and constructed by cold-rolling a flexible and potassiphilic interconnected mediator on the potassium metal surface. The mediator refers to a honeycomb porous carbon structure with uniformly dispersed CoWO4 nanoparticles (denoted UF-CoWO4 NPs/PC). According to theoretical designs and experimental results, UF-CoWO4 NPs/PC mediator with small Young's modulus and strong adsorption capacity can effectively modulate the surface potential distribution and suppress volume changes during K deposition/stripping, thereby achieving dendrite-free K metal anode interface. As a result, the K@UF-CoWO4 NPs/PC symmetric battery can operate stably for more than 1800 h at 0.5 mA cm−2/0.5 mAh cm−2 in carbonate electrolyte without short circuit. The energy and power densities of the K@UF-CoWO4 NPs/PC||KVPO4F full cell are as high as 430.5 Wh kg−1 and 12.1 kW kg−1, respectively, which are significantly better than previously reported potassium metal batteries. This work provides a new avenue for assembling dendrite-free and high-energy potassium metal batteries.