Congener Substitution Reinforced Li₇P_2.9Sb_0.1S_10.75O_0.25 Glass-Ceramic Electrolytes for All-Solid-State Lithium–Sulfur Batteries

Abstract

Glass-ceramic sulfide solid electrolytes like Li7P3S11 are practicable propellants for safe and high-performance all-solid-state lithium–sulfur batteries (ASSLSBs); however, the stability and conductivity issues remain unsatisfactory. Herein, we propose a congener substitution strategy to optimize Li7P3S11 as Li7P2.9Sb0.1S10.75O0.25 via chemical bond and structure regulation. Specifically, Li7P2.9Sb0.1S10.75O0.25 is obtained by a Sb2O5 dopant to achieve partial Sb/P and O/S substitution. Benefiting from the strengthened oxysulfide structural unit of POS3 3– and P2OS6 4– with bridging oxygen atoms and a distorted lattice configuration of the Sb–S tetrahedron, the Li7P2.9Sb0.1S10.75O0.25 electrolyte exhibits prominent chemical stability and high ionic conductivity. Besides the improved air stability, the ionic conductivity of Li7P2.9Sb0.1S10.75O0.25 could reach 1.61 × 10–3 S cm–1 at room temperature with a wide electrochemical window of up to 5 V (vs Li/Li+), as well as good stability against Li and Li–In alloy anodes. Consequently, the ASSLSB with the Li7P2.9Sb0.1S10.75O0.25 electrolyte shows high discharge capacities of 1374.4 mAh g–1 (0.05C, 50th cycle) at room temperature and 1365.4 mAh g–1 (0.1C, 100th cycle) at 60 °C. The battery also presents remarkable rate performance (1158.3 mAh g–1 at 1C) and high Coulombic efficiency (>99.8%). This work provides a feasible technical route for fabricating ASSLSBs.

Solid Li- and Na-Ion Electrolytes for Next Generation Rechargeable Batteries

“…The ionic conductivity of Li 7 P 2.9 Sb 0.1 S 10.75 O 0.25 is 1.62 × 10 −3 S/cm, and it has the activation energy of 26.6 kJ/mol. 44 Also, Li 7 P 2.9 Sb 0.1 S 10.75 O 0.25 has a good retention in discharge capacity after 50 cycles at room temperature. Recently, a quasi-ternary system of sulfide-based electrolytes is gaining increasing interest, and it is known as chalcogenide glass.…”

“…The high polarizability of the framework is the advantage of the sulfide-based glassy electrolyte. 43 Unfortuantely, several sulfidebased electrolytes are unstable in air and moisture; hence, they must be handled under an inert environment, 44 which increases the cost for both synthesis and processing them for application in batteries.…”

“…Zhao et al provided a strategy of congener substitution, which replaced P with Sb and S with O. 44 Li 7 P 2.9 Sb 0.1 S 10.75 O 0.25 is stable in air and has good electrochemical performance. The ionic conductivity of Li 7 P 2.9 Sb 0.1 S 10.75 O 0.25 is 1.62 × 10 −3 S/cm, and it has the activation energy of 26.6 kJ/mol.…”

Bulk and interface-strengthened Li7P2.9Sb0.1S10.65O0.15I0.2 electrolyte via dual-source doping for all-solid-state lithium-sulfur batteries

“…All the experiments except ball milling were performed in a glove box filled with argon (H 2 O <0.1 ppm, O 2 <0.1 ppm). Li 7 P 3 S 11 solid-state electrolytes were prepared in accordance with a previously reported article [29].…”

“…However, some critical issues, such as ionic conductivity, electrolyte stability, and electrolyte/electrode interface compatibility, need to be resolved [23][24][25][26][27]. In ambient air, the sulfide solid electrolyte will be hydrolyzed to release the toxic gas hydrogen sulfide, which destroys the electrolyte structure, leading to decreases in the ion conductivity and degradation of the battery performance [28,29]. Meanwhile, the presence of lithium dendrites at the interface between the solid electrolyte and the anode will cause a rapid short circuit during cycling [30,31].…”