A Bifunctional Perovskite Promoter for Polysulfide Regulation toward Stable Lithium–Sulfur Batteries

Abstract

Lithium-sulfur (LiS) batteries are strongly considered as the next-generation rechargeable cells. However, both the shuttle of lithium polysulfides (LiPSs) and sluggish kinetics in random deposition of lithium sulfides (Li S) significantly degrade the capacity, rate performance, and cycling life of LiS cells. Herein, bifunctional Ba Sr Co Fe O perovskite nanoparticles (PrNPs) are proposed as a promoter to immobilize LiPSs and guide the deposition of Li S in a LiS cell. The oxygen vacancy in PrNPs increases the metal reactivity to anchor LiPSs, and co-existence of lithiophilic (O) and sulfiphilic (Sr) sites in PrNP favor the dual-bonding (LiO and SrS bonds) to anchor LiPSs. The high catalytic nature of PrNP facilitates the kinetics of LiPS redox reaction. The PrNP with intrinsic LiPS affinity serves as nucleation sites for Li S deposition and guides its uniform propagation. Therefore, the bifunctional LiPS promoter in LiS cell yields high rate performance and ultralow capacity decay rate of 0.062% (a quarter of pristine LiS cells). The proposed strategy to immobilize LiPSs, promotes the conversion of LiPS, and regulates deposition of Li S by an emerging perovskite promoter and is also expected to be applied in other energy conversion and storage devices based on multi-electron redox reactions.

Multifunctional Heterostructures for Polysulfide Suppression in High‐Performance Lithium‐Sulfur Cathode

“…The O 1s spectra of DCC@MoS 2 /PrNP/CNTs display three peaks at 533.7, 532.6, and 531.4 eV representing hydroxyls, adsorbed oxygen, and lattice oxygen, respectively . Compared to the primary O 1s spectra, the chemisorption of Li 2 S 6 generates an extra peak at 529.5 eV . This further demonstrates the chemical bonding between O and Li as illustrated in Figure f.…”

“…As illustrated in Figure e, the S 2p core spectra of DCC@MoS 2 /PrNP/CNTs‐Li 2 S 6 show four peaks; two of the peaks are situated at 163.9 and 165.2 eV, respectively, which are assigned to the terminal and bridging sulfur, while another two peaks between 170.6 and 172.1 eV are attributed to the binding energy of thiosulfate and polythionate complex, respectively, which are caused by the polysulfide redox reaction with DCC@MoS 2 /PrNP/CNTs. The O 1s spectra of DCC@MoS 2 /PrNP/CNTs display three peaks at 533.7, 532.6, and 531.4 eV representing hydroxyls, adsorbed oxygen, and lattice oxygen, respectively . Compared to the primary O 1s spectra, the chemisorption of Li 2 S 6 generates an extra peak at 529.5 eV .…”

Enhancing Catalytic Activity of Titanium Oxide in Lithium–Sulfur Batteries by Band Engineering

“…The average discharge capacities can attain 1181, 944, 813, 717, 597, and 399 mAh g −1 at 0.1, 0.2, 0.5, 1, 2, and 5 C, respectively. [34] This versatile catalyst could also manipulate the cycling performance of Li-S batteries. Even worse is that a sharp capacity drop at 2 C was observed in CNT/TiO 2−x -S electrode.…”

Adsorption‐Catalysis Design in the Lithium‐Sulfur Battery

“…[1][2][3][4][5] The main capacity of Li-S battery can be ascribed to the transformation of longchain LiPSs to the short-chain sulfides. In the process of repeated discharge and charge, lithium ions are prone to form uneven deposition on the surface of lithium metal, which generates lithium dendrites and affects the safety and cyclic stability of devices.…”