Regulating f orbital of Tb electronic reservoir to activate stepwise and dual‐directional sulfur conversion reaction

Abstract

The sluggish kinetics in multistep sulfur redox reaction with different energy requirements for each step, is considered as the crucial handicap of lithium–sulfur (Li–S) batteries. Designing an electron reservoir, which can dynamically release electron to/accept electron from sulfur species during discharge/charge, is the ideal strategy for realizing stepwise and dual‐directional polysulfide electrocatalysis. Herein, a single Tb3+/4+ oxide with moderate unfilled f orbital is synthetized as an electron reservoir to optimize polysulfide adsorption via Tb–S and N···Li bonds, reduce activation energy barrier, expedite electron/Li+ transport, and selectively catalyze both long‐chain and short‐chain polysulfide conversions during charge and discharge. As a result, Tb electron reservoir enables stable operation of low‐capacity decay (0.087% over 500 cycles at 1 C), high sulfur loading (5.2 mg cm−2) and electrolyte‐starved (7.5 μL mg−1) Li–S batteries. This work could unlock the potential of f orbital engineering for high‐energy battery systems.

Terbium-induced cobalt valence-band narrowing boosts electrocatalytic oxygen reduction

“…38 Such tunable metal-oxygen covalency donated by the extended hybridization is essential for catalytic performance, such as the obtained high-k dielectric constant for increasing the electronic conductivity. 39,40 Therefore, it is meaningful to select Tb for investigating the 4f-induced electronic interaction with 3d TM species and elucidating the corresponding catalytic promotion mechanism for the ORR.…”

Balanced Mass Transfer and Active Sites Density in Hierarchical Porous Catalytic Metal–Organic Framework for Enhancing Redox Reaction in Lithium–Sulfur Batteries

“…(Figure S26). In the LSB with PP separator, the slow SRR processes can be clearly observed by corresponding characteristic peaks of S 8 (150, 220, and 470 cm –1 ), Li 2 S 6 (396 cm –1 ), Li 2 S 5 (118 cm –1 ), and Li 2 S 4 (201 cm –1 , 453 cm –1 ) in the cathode side (Figure a,b). Specifically, the intensity of the characteristic peaks of LiPSs remains strong even at the end of the discharge process (∼1.7 V), indicating the severe shuttle of LiPSs throughout the whole charging-discharge processes.…”

“…The chemical interaction mechanism between Li 2 S 6 and In general, the nucleation of Li 2 S involves a liquid−solid conversion process in the cycling of LSBs, which is the ratelimiting step in the electrochemical reaction processes. Li 2 S potentiostatic precipitation experiments were conducted to investigate the nucleation of Li 2 S. 41 As shown in Figure 4f, the HPC-MOF-M electrode exhibits the earliest nucleation time (1430 s) and the largest nucleation capacity of Li 2 S (184.0 mAh g −1 ) compared to Ti-MOF-NH 2 (1750 s and 128.8 mAh g −1 ), HPC-MOF-S (1680 s and 138.8 mAh g −1 ), and HPC-MOF-O (1550 s and 162.9 mAh g −1 ), indicating that HPC-MOF-M can significantly promote the nucleation of Li 2 S. The catalytic performance trend based on the test data is summarized as HPC-MOF-M > HPC-MOF-O > HPC-MOF-S > Ti-MOF-NH 2 . The superiority of HPC-MOF-M over HPC-MOF-O can be attributed to its high density of catalytic metal clusters, while HPC-MOF-M outperforms HPC-MOF-S and Ti-MOF-NH 2 due to its hierarchical porous structure.…”

Polyaniline-Coated Cobalt–Iron Oxide Composites Modified Separator for High Performance Lithium–Sulfur Batteries

“…37 Figure 6a illustrates the initial galvanostatic charging and discharging curves of batteries with different separators at 0.1 C. Notably, two prominent discharge platforms appeared around 2.3 and 2.1 V, indicating that S 8 was first converted to higher-order polysulfides and subsequently reduced to lowerorder polysulfides. 38,39 Figure 6b displays the cycling performance of batteries utilizing various separators. The preliminary capacities are recorded as 1489.4, 1390.5, and 1254.1 mAh•g −1 for PP-CFOP, PP-CFO and PP, respectively.…”