Fracture-induced aging anomalies in LiNi0.6Mn0.2Co0.2O2 electrodes

Abstract

The gradual loss of capacity and increase in the cell impedance are the mainstream of aging patterns for the lithium-ion batteries and mainly result from the depletion of cell's cyclable-lithium reservoir. The irreversible drain from this reservoir is well understood and originates from the phenomena such as electrolyte oxidation and reduction at the electrode/electrolyte interfaces. There is, however, limited knowledge about the circumstances leading to the recuperation of misplaced lithium, gain in cell's energy, and impedance drop. Here, we showcase that the intragranular fracture induces a peculiar aging behavior in the LiNi0.6Mn0.2Co0.2O2 electrodes. Fracture enables an alternative path for the (de)insertion of lithium from the hard-to-reach center of the secondary particles by lithium pore-wall flux instead of solid-state diffusion. The possible consequences are the energy recovery and decrease of the charge-transfer resistance in the electronically well wired electrodes.