context: The crystal structure of the current collectors was characterized using a Rigaku D/max-2200/PC X-ray diffractometer (XRD) with Cu Kα radiation (λ = 0.154 nm). The surface morphology of the samples was observed via field-emission scanning electron microscopy (FE-SEM, JEOL, JSM-6700F). Specifically, to characterize the morphology of the lithium metal anodes (LMAs), the coin cells were initially disassembled, the LMAs were extracted and rinsed with DOL/DME cosolvent to remove the residual electrolyte, and finally dried in a glove box. The LMAs were sealed in an air-tight plastic sample box before transferring them from the glove box to the SEM chamber. The coin cells were assembled with the abovementioned protocol in an argon-filled glove box. Coulombic efficiencies (CEs) were tested under different current densities and capacities at room temperature using a LAND battery test instrument. A certain amount of Li metal was initially electrodeposited on an NPAuLi3@NF or NF current collector, and then the cell was charged to 0.1 V (vs. Li+/Li) to strip the Li metal. The cut-off voltage of 0.1 V was set to prevent dealloying of the AuLi alloy. For long-term cycling and full cell tests, 3 mA h cm−2 of Li metal was firstly deposited on the current collectors, and then the cells were subjected to charge/discharge cycling at different current densities and capacities. LiFePO4 with an areal mass loading of 1.72 mg cm−2 was used as the cathode material in the full cell tests. The electrochemical impedance spectroscopy (EIS) study was conducted using a ZIVE SP1 electrochemical workstation in the frequency range of 100 kHz to 10 MHz with an AC potential amplitude of 5 mV.
answer: LiFePO4 