1. (a) Long-term cycling performance and (b) corresponding discharge-charge curves of CoS₂ cathode in different hybrid electrolytes at 0.1C and 0.1-2.0 V; (c) Electrochemical cycling performance and (d) corresponding discharge-charge curves of CoS₂ cathode in LiCl-APC electrolytes with different Li-salt concentrations

2. (a) Comparison of long-term performance of Mg-CoS₂ cells under different voltage ranges based on LiCl-APC electrolyte at 0.1C; (b) Rate performance of Mg-CoS₂ cells under different voltage ranges based on LiCl-APC electrolyte

3. XPS spectra of (a) Co2p and (b) S2p for pristine CoS₂ electrode, 1st discharged electrode and electrodes after 1st charge to 2.0 and 2.75 V

4. (a, c, e) TEM and (b, d, f) HRTEM images of CoS₂ electrode after (a, b) first discharge, first charge to (c, d) 2.0 and (e, f) 2.75 V

5. (a) SEM image and (b-f) element mappings of Mg anode surface from Mg-CoS₂ cell in LiCl-APC electrolyte after 50 cycles

6. Schematic illustration of charge/discharge processes of Mg-CoS₂ cells based on Li⁺/Mg²⁺ hybrid electrolyte in different voltage ranges

7. Galvanostatic charge/discharge curves of (a)Li/CoS₂ (LMB) and (b)Mg/CoS₂ (MLB) cells during first two cycles for comparison between thermodynamic voltage and practical discharge voltage

S1. (a) XRD pattern of commercially available CoS₂, (b) SEM image of CoS₂ cathode before cycling

S2. Discharge-charge curves of CoS₂ cathode in pure APC electrolyte

S3. Discharge-charge curves of Li-CoS₂ battery during the first 20 cycles

S4. XRD pattern of as-synthesized Co₃S₄ sample

S5. (a) Long-term cycling performance and (b) corresponding discharge-charge curves of Co₃S₄ cathode in 1 mol/L LiCl-APC electrolyte