Tailored Li₇P₃S₁₁ Electrolyte by In₂S₃ Doping Suppresses Electrochemical Decomposition for High-Performance All-Solid-State Lithium–Sulfur Batteries

Abstract

The retentive functional intimate contact at the solid electrolyte/cathode interface and among the cathode components, for example, solid electrolyte, a conductive additive, and active material (S/Li 2 S), is essential for high-performance solid-state lithium−sulfur batteries. Currently, thiophosphate-based electrolytes are plagued by failure at the interfaces due to the intrinsically narrow electrochemical stability window, which in principle, derive uneven irreversible redox reactions at the triple point of contact, which result in sulfur-and phosphorus-enriched interphases (e.g., Li 3 P, P 2 S X , S, Li 2 S n , etc.), retard Li + conduction, and increase the interface resistance. Herein, structural tuning of Li 7 P 3 S 11 was done using the In 2 S 3 dopant, and the designed Li 6.93 P 2.97 In 0.02 S 10.92 electrolyte presented better σ Li+ of 2.9 mS cm −1 and enhanced air stability @ RT. Furthermore, In 2 S 3 broadened the electrochemical stability window and suppressed the redox decomposition of Li 7 P 3 S 11 at the interface in the Li 2 S-composite cathode layer, ensuring effective (ionic/electronic) conduction. Therefore, the Li 2 S/Li 6.93 P 2.97 In 0.02 S 10.92 /Li−In cell offers a high discharge capacity of 946.75 mA h g −1 with an ∼100% average Coulombic efficiency over 30 cycles. Moreover, the cell with Li 6.93 P 2.97 In 0.02 S 10.92 presented a low interfacial resistance of 127 compared to 383 Ω for counterparts over 30 cycles, which could be benefitted from suppressed redox decomposition of the solid electrolyte and long-lasting intimate contact at the triple point of contact. Thus, the projected doping strategy developed a sulfide electrolyte to address the chemical/electrochemical stabilities and redox decomposition of sulfide electrolytes for the next-generation all-solid-state technologies. KEYWORDS: Li 6.93 P 2.97 In 0.02 S 10.92 glass ceramic, air stability, low redox decomposition, stable solid electrolyte/cathode interface, all-solid-state lithium−sulfur batteries

Experimental Discovery of a Fast and Stable Lithium Thioborate Solid Electrolyte, Li6+2x[B10S18]Sx (x ≈ 1)

“…For LBS reduction, we scanned between 0 and 1.8 V. There, the reduction starts at 1.3 V (Figure d). Therefore, the electrochemical stability window of LBS is 1.3–2.5 V. This window is considerably wider than those of the majority of sulfide solid electrolytes (Figure S6) ,− such as β-Li 3 PS 4 , Li 7 P 3 S 11 , Li 10 GeP 2 S 12 , Li 10 SnP 2 S 12 , and Li 6 PS 5 Cl within the Li|SSE|SSE+C test cell configuration. To ensure a fair comparison, we specifically chose pristine sulfide electrolytes (without any dopants or coatings) and determined the range of the electrochemical stability window based on the onset voltage.…”

Enhanced Ionic Conductivity toward Air-Stable Li4SnS4 Solid Electrolytes Achieved by Soft Acid Bi3+ Doping

“…The spectra of Sn 3d in the gc-LSS and gc-LSB 0.025 S show similar shapes, which are depicted in Figure a,c, respectively. They both exhibit the typical peaks corresponding to Sn 3d 5/2 and Sn 3d 3/2 at about 485.7 and 494.2 eV, respectively. , In addition, in the S 2p spectrum for gc-LSS, the peaks at 161.5 and 161.9 eV are associated with Sn–S–Li and SnS bonds, respectively (Figure c). , As for gc-LSB 0.025 S, except for SnS and Sn–S–Li bonds, the S 2p spectrum shows a couple of peaks at 157.6 and 163.1 eV in agreement with Bi 4f 7/2 and Bi 4f 5/2 , respectively, due to the strong binding energy closeness between Bi 4f and S 2p (Figure d). , Consequently, we conclude that Bi 3+ can successfully substitute Sn 4+ in the lattice of Li 4 SnS 4 based on the combined results of XRD, XPS, and Raman.…”

Active Regulation Volume Change of Micrometer‐Size Li2S Cathode with High Materials Utilization for All‐Solid‐State Li/S Batteries through an Interfacial Redox Mediator

“…The electrolyte was synthesized according to the previous research reports. [ 11 ] The Li 2 S (Alfa, 99.9%) and P 2 S 5 (Macklin, 99.99%) with a mole ratio of 7:3 as the raw materials were mixed and ball milled at 510 rpm for 45 h, followed by heating at 280 °C for 2 h to get the glass‐ceramics Li 7 P 3 S 11 SSE.…”