Electrochemical Alloying of Lead in Potassium-Ion Batteries

The electrochemical alloying of lead-based electrodes with potassium was investigated by galvanostatic measurements as well as by ex situ and operando X-ray diffraction. The electrochemical reduction must be activated by an initial high current pulse which prevents the passivation of the lead electrode. The alloying process leads to the formation of crystalline KPb. During the discharge, two intermediate phases are observed, K₁₀Pb₄₈ and K₄Pb₉, whereas only K₄Pb₉ seems to form during the charge. High capacity retention is observed, with, however, a limited specific capacity value because of high weight of lead.