Analysis of electrochemical performances in hybrid lithium-ion/lithium metal battery during charging

High energy density and stable capacity are achieved in hybrid lithium-ion/lithium metal batteries (HLBs) via combination of lithium intercalation and plating reactions. Coupling Butler-Volmer equation and extended Ohm's law with species transport, Doyle-Fuller-Newman (DFN) framework customized for HLBs in pseudo-threedimensional (P3D) model is developed to analyze variations of electrochemical parameters in HLB with charging in lithium-ion (Li-ion) mode converting to lithium metal (Li-metal) mode, and among lithium-ion battery (LIB), lithium metal battery (LMB) and HLB during charging. Comparison of cell voltage and lithium deposition rate between in LMB and in HLB with dendrites or no on surface of anode, as well as the effects of applied current density on total cell capacity and its proportion of capacity in Li-ion mode or Li-metal mode are investigated in HLB during charging. The cut-off voltage rises from 3.95 V to 4.4 V with charging from in Li-ion mode to Li-metal mode. The increase in charging current from 0.2C to 1C leads to the decrease in total cell capacity and its proportion of capacity in Li-metal mode from 232 mAh to 32.2 % to 169.7 mAh and 9.3 %. All results can provide valuable insights for the development and application of HLB to obtain electrochemical performances.