Chi604e

Before test, the Li anode was stored in different conditions. For instance, the pristine Li and RI||Li were exposed in dry room (RH = 1.55%, temperature ~ 25 °C) with scheduled 7 days for the case of investigating the environmental tolerance of dry room. For the symmetrical Li||Li manufacturing, the coin cells (CR-2032 or 2025) were adopted to assemble the symmetrical cell. Celgard 2400 polypropylene (PP) was used as the separator. The electrochemical performance was monitored using a cell cycler (CT200 A, Wuhan LAND Electronic Co., Ltd). Electrochemical impedance spectroscopy (EIS) was performed on CHI660E or CHI604E electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd).
For the preparation of S electrode applied for coin cell, typically, commercial AB, S powder, and PVDF powder with a mass ratio of 3:6:1 were firstly mixed in NMP solvent, stirred for 24 h under the protection of Ar atmosphere, and then were uniformly cast on the surface of carbon coated aluminum foil. For pouch cell tests, a similar method was used for the slurry except the electrode was double-coated. The average loading of S for coin cell tests is ~ 1 mg cm⁻², and for pouch cell is ~ 5 mg cm⁻² (single side). The amounts of the electrolyte in Li symmetric cells, Li–S coin cells, and Li–S pouch cells are 30 µL/cell, 30 µL/mg, and 4 µL/mg, respectively.

The native and PPy-coated Chlorella cells were washed using DI water and centrifugation (3775 × g, 3 min), and then immersed in nafion solution (0.5%, v/v). Then, one drop of the cell suspension was added onto a carbon cloth substrate and dried overnight at room temperature. For fabrication of a three-electrode system, the working electrode was the cell-attached carbon cloth substrate, a platinum wire was the counter electrode, and Ag/AgCl was used as reference electrode. PBS (pH = 7.0, 0.1 M) containing 100 mM of NaCl was chosen as the electrolyte. The samples were then conducted on the electrochemical workstation (Chenhua CHI604E, Shanghai, China) at the scanning rate of 200 mV/s.

The morphology of the material was examined by scanning with an electron microscope (SEM, HITACHI S4800, Hitachi Ltd., Tokyo, Japan) and a transmission electron microscope (TEM, JSM-2010HR, JEOL Ltd., Tokyo, JapanFEI). The crystal structure was analyzed using a X-ray diffractometer (XRD, Dmax 2200, Rigaku Ltd., Tokyo, Japan) with Cu Kα radiation (λ = 0.15418 nm). The wettability of composite materials to electrolyte was evaluated by a contact angle tester (OCA15EC, Dataphysics, Stuttgart, Germany). The chemical bonds of samples were investigated by Fourier-transform infrared (FTIR, Analect Company, New York, NY, USA); X-ray photoelectron spectroscopy (XPS, ESCALAB250, Thermo Fisher Scientific Ltd., Waltham, MA, USA) was used to evaluate the chemical state of the sample surface. Electrochemical impedance spectroscopy (EIS, 0.1–100,000 Hz) and cyclic voltammetry (CV, 1.7–2.7 V, 0.01 mV/s) were tested by an electrochemical workstation (CHI 604E, Chenhua, Shanghai, China). A constant current charge and discharge measurement was performed on a LAND battery system (CT 200, Wuhanlanbo, Wuhan, China) at room temperature.