Suppression of lithium dendrite by using scaffolds derived from MOFs

Abstract

Lithium metal batteries (LMBs) are widely regarded as the next generation batteries beyond Li-ion batteries (LIBs) owing to its high theoretical energy densities. However, before LMBs become reliable energy storage devices, lithium dendrite induced safety and cycling challenges on the anode should be addressed. In the present study, 2D porphyrin paddle-wheel frameworks-3 (PPF-3) microsheets were synthesized through a polyvinylpyrrolidone (PVP) assisted solvothermal method and then tested as a suitable scaffold for Li dendrite suppression with good cycling performance achieved. For the half-cell test, at a current density of 0.5 mA/cm2 with an areal capacity of 1 mAh/cm2 in each half cycle, the cycling Coulombic efficiencies (CE) of the PPF-3 microsheet/Cu can be maintained well above 97.3% over 200 cycles. For the symmetrical cell test, at 1 mA/cm2 with 1 mAh/cm2 Li deposition in each half cycle, the voltage-time profile of Li/PPF-3 microsheets/Cu remains stable with relatively small overpotential of ~0.1V even after 300 h. From scanning electron microscope (SEM) observation, the PPF-3 microsheets modified lithium anode exhibits a homogenous Li deposition behavior without dendrite growth, which can be explained by the strongly increased surface area of 2D microsheets, the corresponding enhanced electrolyte uptake and exposed functional groups.