Key Takeaways & Executive Findings
- •• A volcano-type relationship between catalytic activity and vacancy concentration is revealed, highlighting the trade-off between activity and stability. • A novel “heteroatoms synergistic anchoring vacancies” strategy is proposed, achieving P-doped CoSe2 with rich selenium vacancies (P-CS-Vo-0.5) that balances high activity and structural stability. • P doping lowers Se vacancy surface energy and effectively “pins” active sites, suppressing dynamic migration of vacancies and enhancing catalytic stability. • The optimized P-CS-Vo-0.5 separator enables ultrahigh capacity and stability in Li–S batteries, achieving 95.1% capacity retention after 80 cycles at high sulfur loading.
Abstract
Electrocatalyst activity and stability demonstrate a “see-saw” relationship. Introducing vacancies (Vo) enhances the activity by improving reactant affinity and increasing accessible active sites. However, deficient or excessive Vo reduces polysulfide adsorption and lowers catalytic stability. Herein, a novel “heteroatoms synergistic anchoring vacancies” strategy is proposed to address the trade-off between high activity and stability. Phosphorus-doped CoSe2 with remained rich selenium vacancies (P-CS-Vo-0.5) was synthesized by producing abundant selenium Vo followed by controlled P atom doping. Atomic-scale microstructure analysis elucidated a dynamic process of surface vacancy generation and the subsequent partial occupation of these vacancies by P atoms. Density functional theory simulations and in situ Raman tests revealed that the Se vacancies provide highly active catalytic sites, accelerating polysulfide conversion, while P incorporation effectively reduces the surface energy of Se vacancies and suppresses their inward migration, enhancing structural robustness. The battery with the optimal P-CS-Vo-0.5 separator delivers an initial discharge capacity of 1306.7 mAh g−1 at 0.2C, and maintain 5.04 mAh cm−2 at a high sulfur loading (5.7 mg cm−2, 5.0 μL mg−1), achieving 95.1% capacity retention after 80 cycles. This strategy of modifying local atomic environments offers a new route to designing highly active and stable catalysts.
1. Introduction
Lithium-sulfur batteries (LSBs) have been considered promising candidates for next-generation energy storage due to high theoretical energy density (2600 Wh kg−1) and capacity (1675 mAh g−1) [1, 2]. The shuttle effect and slow sulfur conversion kinetics result in low sulfur utilization and rapid capacity decay, seriously hindering the practical application of LSBs [3, 4]. Polar catalysts (e.g., materials featuring polar groups or unsaturated coordination metal centers) mitigate the shuttle effect and enhance sulfur utilization by facilitating lithium polysulfide (LiPSs) conversion, modulating adsorption behavior, and improving ion transport [5, 6].
Cobalt selenide (e.g., CoSe2) is widely used in catalysis due to its excellent physicochemical properties, and its overall performance surpasses that of other metal selenides, such as FeSe2, NiSe2, and MoSe2 [6]. Firstly, CoSe2 exhibits strong adsorption of LiPSs because the d-orbital electrons of cobalt, especially in the eg orbital, form strong covalent bonds with sulfur atoms, effectively suppressing the shuttle effect. Secondly, CoSe2 has a high electrical conductivity (around 103 S cm−1), which is much higher than that of semiconducting materials like FeSe2 and MoSe2, facilitating electron transport and enhancing catalytic efficiency. Additionally, CoSe2 features a stable cubic octahedral structure that can accommodate the volume changes of the sulfur cathode during charge–discharge cycles, maintaining structural stability. However, insufficient active site density represents a critical bottleneck limiting catalytic performance enhancement and hindering substantial improvements in efficiency.
Vacancy defect engineering has emerged as an effective strategy for enhancing catalytic activity. Due to the coordinative unsaturation of neighboring atoms, Vo serve as highly active centers promoting strong interactions with reactant molecules [7, 8]. Furthermore, Vo indirectly modulate the electronic structure by introducing defect states and altering the band structure, thereby facilitating reactant adsorption and activation [9, 10]. However, the role of Vo is a double-edged sword: insufficient vacancy concentration limits active sites, hindering effective catalysis, while excessive concentration compromises structural integrity, leading to active site collapse and rapid electrode degradation [11]. Shao et al. demonstrated that a sulfur vacancy concentration below 8% in MoS2 catalysts diminishes the adsorption of LiPSs, consequently reducing catalytic performance [12]. Gao et al. synthesized WSe1.51 with the best polysulfide binding and catalysis, and demonstrated that excessive defects (e.g., W: Se = 1.33) led to structural collapse an
Loading authentic research manuscript (Pages 1–5)...
Xiaoya Zhou, Wei Mao, Chengwei Ye, Qi Liang, Peng Wang, Xuebin Wang, Shaochun Tang (2025). Heteroatoms Synergistic Anchoring Vacancies in Phosphorus-Doped CoSe2 Enable Ultrahigh Activity and Stability in Li–S Batteries. Nano-Micro Letters. https://doi.org/10.1007/s40820-025-01806-0
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoTechIntel claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the main challenge addressed in this study?
The study addresses the trade-off between catalytic activity and stability in lithium-sulfur batteries, where introducing vacancies enhances activity but excessive vacancies compromise structural integrity.
What is the proposed strategy to balance activity and stability?
The authors propose a 'heteroatoms synergistic anchoring vacancies' strategy, where phosphorus doping in CoSe2 with rich selenium vacancies (P-CS-Vo-0.5) stabilizes the vacancies while maintaining high catalytic activity.
How does phosphorus doping improve the catalyst?
Phosphorus doping lowers the surface energy of selenium vacancies, suppressing their inward migration and thus enhancing structural robustness, while the vacancies provide highly active catalytic sites for polysulfide conversion.
What are the key performance metrics of the optimized battery?
The battery with the P-CS-Vo-0.5 separator delivers an initial discharge capacity of 1306.7 mAh g−1 at 0.2C, maintains 5.04 mAh cm−2 at high sulfur loading (5.7 mg cm−2), and achieves 95.1% capacity retention after 80 cycles.
What methods were used to investigate the mechanism?
The study used atomic-scale microstructure analysis, density functional theory (DFT) simulations, and in situ Raman tests to elucidate the dynamic process of vacancy generation and the role of phosphorus doping.
Related Technical Papers & Translations
Direct Repair of the Crystal Structure and Coating Surface of Spent LiFePO4 Materials Enables Superfast Li-Ion Migration
The rapid accumulation of spent LiFePO4 (LFP) cathodes from retired lithium-ion batteries necessitates the development of effective and environmental-friendly recycling strategies. In this context, direct regeneration has emerged as a promising approach for reclaiming LFP cathode materials, offering a streamlined pathway to restore their electrochemical functionality. We report an integrated regeneration protocol that simultaneously repairs the degraded crystal structure and reconstructs the damaged carbon coating in spent LFP. The regenerated cathode material had superfast lithium-ion diffusion kinetics and a stable cathode–electrolyte interface, giving a remarkable rate capability with specific capacities of 122 mAh g−1 at 5C and 106 mAh g−1 at 10C (1C = 170 mA g−1). It also maintained capacities of 110.7 mAh g−1 (5C) and 84.1 mAh g−1 (10C) after 400 cycles. It could be used in harsh environments and could be stably cycled at subzero temperatures (−10 and −20 °C) and in solid-state electrolyte batteries. Life cycle assessment combined with economic evaluation using the EverBatt model reveals that this direct regeneration approach has high economic and environmental benefits.
Oxide Semiconductor for Advanced Memory Architectures: Atomic Layer Deposition, Key Requirement and Challenges
Oxide semiconductors (OSs), introduced by the Hosono group in the early 2000s, have evolved from display backplane materials to promising candidates for advanced memory and logic devices. The exceptionally low leakage current of OSs and compatibility with three-dimensional (3D) architectures have recently sparked renewed interest in their use in semiconductor applications. This review begins by exploring the unique material properties of OSs, which fundamentally originate from their distinct electronic band structure. Subsequently, we focus on atomic layer deposition (ALD), a core technique for growing excellent OS films, covering both basic and advanced processes compatible with 3D scaling. The basic surface reaction mechanisms—adsorption and reaction—and their roles in film growth are introduced. Furthermore, material design strategies, such as cation selection, crystallinity control, anion doping, and heterostructure engineering, are discussed. We also highlight challenges in memory applications, including contact resistance, hydrogen instability, and lack of p-type materials, and discuss the feasibility of ALD-grown OSs as potential solutions. Lastly, we provide an outlook on the role of ALD-grown OSs in memory technologies. This review bridges material fundamentals and device-level requirements, offering a comprehensive perspective on the potential of ALD-driven OSs for next-generation semiconductor memory devices.
Laser powder bed fusion of biodegradable Zn-4Cu alloy: Processing, microstructure and properties
Zn's natural degradability and biocompatibility make it a promising candidate for implants, however, its mechanical properties remain insufficient for bone applications. In this study, the performance of Zn was enhanced by developing Zn-Cu alloys via laser powder bed fusion (LPBF). Optimal LPBF parameters for forming stable tracks were achieved by adjusting laser power and scanning speed. Under optimized conditions of 100 W and 100 mm/s, high-density (99.58%) Zn-Cu alloys with improved hardness (68.2HV) and yield strength (160 MPa) were achieved. These improvements are attributed to solid solution strengthening, segregation strengthening, and grain refinement. The Zn-Cu alloys also demonstrated favorable degradation behavior, with a rate of 0.16 mm/year. This degradation is primarily driven by micro-galvanic corrosion between the CuZn5 phase and Zn matrix, along with refined grains and increased grain boundary density. This work demonstrates a viable strategy for fabricating Zn-based implants with enhanced structural integrity and mechanical performance via LPBF.