A Tellurium‐Boosted High‐Areal‐Capacity Zinc‐Sulfur Battery

Abstract Aqueous rechargeable zinc‐sulfur (Zn‐S) batteries are a promising, cost‐effective, and high‐capacity energy storage technology. Still, they are challenged by the poor reversibility of S cathodes, sluggish redox kinetics, low S utilization, and unsatisfactory areal capacity. This work develops a facile strategy to achieve an appealing high‐areal‐capacity (above 5 mAh cm−2) Zn‐S battery by molecular‐level regulation between S and high‐electrical‐conductivity tellurium (Te). The incorporation of Te as a dopant allows for manipulation of the Zn‐S electrochemistry, resulting in accelerated redox conversion, and enhanced S utilization. Meanwhile, accompanied by the S‐ZnS conversion, Te is converted to zinc telluride during the discharge process, as revealed by ex‐situ characterizations. This additional redox reaction contributes to the S cathode's total excellent discharge capacity. With this unique cathode structure design, the carbon‐confined TeS cathode (denoted as Te1S7/C) delivers a high reversible capacity of 1335.0 mAh g−1 at 0.1 A g−1 with a mass loading of 4.22 mg cm−2, corresponding to a remarkable areal capacity of 5.64 mAh cm−2. Notably, a hybrid electrolyte design uplifts discharge plateau, reduces overpotential, suppresses Zn dendrites growth, and extends the calendar life of Zn‐Te1S7 batteries. This study provides a rational S cathode structure to realize high‐capacity Zn‐S batteries for practical applications.


Figure S2 .
Figure S2.(a) Nitrogen adsorption/desorption isotherm of KB, and (b) pore size distribution of KB host.

Figure S4 .
Figure S4.Preparation procedures of the free-standing Te1S7/C electrodes.

Figure S6 .
Figure S6.CV plots of (a) Zn-S/C and (b) Zn-Te1S7/C batteries at the scan rate of 0.2 mV s -1 .

Figure S9 .
Figure S9.Galvanostatic charge/discharge profiles of the Te1S7/C cathode cast onto Ti foil with the mass loading of 0.6 mg cm -2 tested at 0.1 A g -1 .

Figure S11 .
Figure S11.Reaction resistance of Zn-S/C and Zn-Te1S7/C batteries from GITT plots in Figure

Figure S14 .
Figure S14.Galvanostatic charge/discharge profiles of the Zn-Te1S7/C battery with various mass loadings at 0.5 A g -1 .

Figure S16 .
Figure S16.(a) TEM, (b) HRTEM, and (c) SAED images of the S/C electrode after being discharged to 0.1 V.

Figure S17 .
Figure S17.HADDF image and elemental mapping of the discharged S/C cathode.

Figure S18 .
Figure S18.Optical microscopy images of Zn surface after 5 cycles of Zn plating/stripping in (a, b) aqueous and (c, d) hybrid electrolytes.

Figure S19 .
Figure S19.Areal capacities of the Zn-Te1S7 battery over 20 cycles with a hybrid electrolyte tested at 0.2 A g -1 with a cut-off voltage range of 0.1-1.7 V.

Figure S20 .
Figure S20.Specific discharge capacities of the Zn-Te1S7 battery over 25 cycles in the hybrid electrolyte with H2O/TEGDME volume ratios of 9.5:0.5 and 9:1, tested at 0.2 A g -1 with a cutoff voltage range of 0.1-1.7 V.

Table S1 .
Cathode comparison in aqueous Zn-ion batteries.

Table S2 .
EIS impedance values for Zn-S/C and Zn-Te1S7/C batteries.