《Customized Electrolyte and Host Structures Enabling High-Energy-Density Anode-Free Potassium–Metal Batteries》

Potassium has a high abundance and energy density comparable to lithium, so it has great potential to replace lithium in terms of energy storage. However, problems including unstable electrode/electrolyte interface phases, dendrite growth, and volume changes have limited the development of potassium metal batteries. To date, there is no single solution that can deal with these issues once and for all. In this paper, we demonstrate an anode-free potassium metal battery that can simultaneously improve efficiency, reversibility, and energy density by introducing a custom electrolyte and potassium metal host structure. First, a diluted highly concentrated electrolyte with fast kinetics and high stability elicits stable SEI rich in inorganics. At the same time, mesoporous (MCNF) carbonaceous hosts with a narrow distribution range are beneficial for reducing surface area but with sufficient internal space. Together, they achieve a high average coulombic efficiency (CE) of 99.3% and an initial CE of 95.9% at 3 mA cm-2-3 mA h cm-2. Anode-free MCNF|| Prussian blue (PB) potassium batteries can achieve 100 reversible cycles with an energy density of up to 362 W h kg-1.

https://pubs.acs.org/doi/full/10.1021/acsenergylett.3c01067