K+ Reduces Lithium Dendrite Growth by Forming a Thin, Less-Resistive Solid Electrolyte Interphase

Adding 10 mM KPF6 to the 1 M LiPF6 in ethylene carbonate/dimethyl carbonate electrolyte of symmetrical Li vertical bar Li cells eliminated the growth of dendrites at 0.5 mA cm(-2) current density and massively reduced, but did not eliminate, the growth of dendrites at 2.5 mA cm-(2.) The added KPF6 increased the fraction of inorganic salts in the solid electrolyte interface, making it thinner and more Li+ conductive. It overcame the growth of dendrites resulting from inadequate nucleation density but not dendrite growth into the depletion layer, which scales with the layer's thickness, i.e., the current density.