Hybrid Membrane Doubles the Lifetime of Rechargeable Batteries

The energy density of traditional lithium-ion batteries is approaching a saturation point that cannot meet the demands of the future; for example, in electric vehicles. Lithium-metal batteries can provide double the energy per unit weight when compared to lithium-ion batteries. The biggest challenge, however, is the formation of lithium dendrites — small, needle-like structures — over the lithium-metal anode. These dendrites often continue to grow until they pierce the separator membrane, causing the battery to short-circuit and ultimately destroy it. Researchers have developed a solution to prevent dendrite formation and thus at least double the lifetime of a lithium-metal battery. During the charge transfer process, lithium ions move back and forth between the anode and the cathode. Whenever they pick up an electron, they deposit lithium atoms, which accumulate on the anode. A crystalline surface is formed, which grows three-dimensionally where the atoms accumulate, creating the dendrites. The pores of the separator membrane influence the nucleation of dendrites. If ion transport is more homogeneous, dendrite nucleation can be avoided.