Optimization of two-dimensional solid-state electrolyte–anode interface by integrating zinc into composite anode with dual-conductive phases

Abstract

Solid-state electrolytes (SSEs) are a solution to safety issues related to flammable organic electrolytes for Li batteries. Insufficient contact between the anode and SSE results in high interface resistance, thus causing the batteries to exhibit high charging and discharging overpotentials. Recently, we reduced the overpotential of Li stripping and plating by introducing a high proportion of dual-conductive phases into a composite anode. The current study investigates the interface resistance and stability of a composite electrode modified with Zn and a lower proportion of dual-conductive phases. Zn-cation-adsorbed Prussian blue is synthesized as an intermediate component for a Zn-modified composite electrode (Li-FeZnNC). The Li-FeZnNC symmetric cell presents a lower interface resistance and overpotential compared with Li-FeNC (without Zn modification) and Li-symmetric cells. The Li-FeZnNC symmetric cell shows high electrochemical stability during Li stripping and plating at different current densities and high stability for 200 h. Full batteries with a Li-FeZnNC composite anode, garnet-type SSE, and LiFePO₄ cathode show low charging and discharging overpotentials, a capacity of 152 mAh g⁻¹, and high stability for 200 cycles.