Lithiophilic sites dependency of lithium deposition in Li metal host anodes

Abstract

Lithiophilic hosts hold exciting prospects to tackle the challenges of the dendrite growth and volume expansion of Li metal anode. However, insight into the structure of lithiophilic sites on impacting Li deposition which determines the reliability of electrode yet remains elusive. Here, based on nonlinear phase-field simulations, we show that the Li-ion flux in the electrolyte and current density on the electrode surface are closely related to the dispersity of lithiophilic sites. Taking ZnO as an example, we also experimentally demonstrate that host with densely and homogenously distributed ZnO nanodots allows uniform Li nucleation and even Li deposition compared to its counterparts with separately dispersed and randomly coalesced morphologies. Consequently, symmetric cell with the well-designed anode delivers a long-term lifespan of 1300 h with a low overpotential of only 11 mV. Further coupling with a sulfurized polyacrylonitrile cathode, the full cell displays a steady capacity of 1120 mA h g−1 for 800 cycles at 1 C and a superb rate capacity of 702 mA h g−1 at 5 C. These findings correlate the structure of lithiophilic sites with the mesostructure evolution of Li during deposition, and would provide useful guidance for the host designs toward high-performance rechargeable Li batteries.