High rate, long cycle life potassium metal anode based on multifunctional nanodot additives

Abstract

Potassium mental batteries (PMBS) have received keen concern in energy storage and supply, because of its high energy density and abundant resources. Whereas, the high reactivity of potassium metal resulted in side reactions and dendrites growth, which can significantly affect commercial application of the batteries. In this work, the carbon dots (CDs) are introduced as an electrolyte additive to inhibit side reactions and dendrites growth. The surface of ultrasmall CDs is modified by electronegative functional groups, which make it provide abundant active sites for ion transfer and show affinity for K⁺, which can adsorb K⁺ to achieve uniform deposition. The K||K symmetric cells with CDs can cycle steadily more than 1000 h, and the limited current density can reach 5.5 mA cm⁻². The work is simple and easy to implement, with good universality, providing an effective solution strategy for the application of high rate, long-life potassium metal batteries.