Beyond isolated optimization: a holistic review across the pre‑mid post‑treatment chain for hard carbon in sodium‑ion battery
Shanghai Jiao Tong University Journal Center
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- Proposes a holistic “Pre-Mid-Post” full-process engineering mode to go beyond fragmented single-point optimization of hard carbon anodes
- Elucidates the synergistic and contradictory interplay among graphitic domains, nanopores, and defects in determining the Na⁺ storage properties
- Future design necessitates cross-stage co-optimization and quantitative microstructure–performance relationships for rational HC engineering
Credit: Qingxuan Geng, Yonghui Zhang, Dongxu Xie, Chenhui Hao, Liping Guo, Jiwei Zhang*, Paul K. Chu*, Qingwei Li*.
As the global energy transition accelerates, sodium-ion batteries (SIBs) are emerging as a compelling alternative to lithium-ion systems, offering superior low-temperature performance, enhanced safety, and faster charging at a fraction of the cost. Yet, the commercialization bottleneck remains locked in the anode—specifically, hard carbon (HC), the only commercially viable anode material for SIBs today. Now, researchers from Qilu University of Technology, Henan University, City University of Hong Kong, and Wuhan University of Science and Technology, led by Professor Qingwei Li, Professor Jiwei Zhang, and Professor Paul K. Chu, have delivered a landmark review that redefines how we engineer HC from the ground up.
Why This Review Matters
Traditional HC research has long been trapped in a fragmented paradigm—optimizing precursors, pyrolysis, or post-treatment in isolation. These single-point improvements often yield disappointing results because they ignore the intricate synergies and trade-offs across the entire fabrication chain. This work shatters that paradigm by proposing a holistic "Pre-Mid-Post" full-process engineering framework, treating HC development as a systematically coordinated chain rather than a collection of disconnected steps.
Innovative Framework and Mechanism
The review first decodes the "house-of-cards" microstructure of HC—randomly oriented graphitic nanodomains, nanopores, and defects—and clarifies how these four core structural features collectively govern sodium storage. It then systematically dissects each stage of the fabrication chain:
Pretreatment Engineering: From hydrothermal crosslinking and chemical crosslinking to pre-oxidation, pre-carbonization, pre-doping, component regulation, and pore-forming treatments. Each strategy is evaluated for its capacity to modulate graphitic domain growth, pore topology evolution, and defect engineering at the precursor stage.
Mid-Pyrolysis Control: The review critically compares conventional slow heating carbonization with next-generation technologies including flash Joule heating (FJH) and microwave-induced heating. Notably, FJH enables millisecond-scale carbonization that suppresses excessive graphitization while preserving expanded interlayer spacing—yielding HC with plateau capacities up to 290 mAh g-1 and energy savings of ~80%.
Post-Treatment Modification: Surface functional group regulation, post-doping, pore filling, surface coating, and pre-sodiation are analyzed as precision "pruning" tools to refine the preformed carbon framework. For instance, fluorine grafting via "grafting technology" achieves ICE up to 90.0% and stable cycling over 5,000 cycles at 2.0 A g-1.
Outstanding Synergies and Trade-offs
The review's analytical depth lies in exposing the dynamic contradictions within HC microstructures: expanded interlayer spacing boosts ion transport but may compromise electronic conductivity; abundant closed pores enhance plateau capacity but require careful control of open-to-closed pore ratios; defects provide active sites yet exacerbate irreversible SEI formation. The authors demonstrate that only cross-stage co-optimization—where pretreatment preconditions mid-pyrolysis outcomes, which in turn dictate post-treatment efficacy—can resolve these antagonistic effects.
Industrial Relevance and Future Outlook
Drawing from commercial benchmarks including Kuraray, ShengQuan Group, and BSG New Energy, the review addresses the critical gap between laboratory innovation and industrial mass production. It emphasizes raw material consistency control, continuous rotary kiln/roller furnace engineering, and batch-to-batch stability as prerequisites for scaling.
Looking forward, the authors chart six strategic directions: (1) establishing multi-scale quantitative structure–performance relationships via advanced characterization and machine learning; (2) developing cross-stage synergistic modification strategies; (3) promoting interdisciplinary integration of computational simulation and in situ characterization; (4) resolving engineering bottlenecks in large-scale fabrication; (5) standardizing precursor physicochemical information disclosure; and (6) harnessing machine learning to accelerate R&D cycles.
Stay tuned for more groundbreaking insights from this collaborative team across Qilu University of Technology, Henan University, City University of Hong Kong, and Wuhan University of Science and Technology!
Journal
Nano-Micro Letters
Method of Research
News article
Article Title
Beyond Isolated Optimization: A Holistic Review Across the Pre‑Mid Post‑Treatment Chain for Hard Carbon in Sodium‑Ion Battery
From passive protection to active regulation: researchers chart the future of zinc-ion batteries with atomic layer deposition
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Schematic illustration of the challenges and atomic layer deposition (ALD) engineering strategies for both cathode and anode in ZIBs
view moreCredit: Kaixin Huang, Shun Zhang, Zewen Liu, Tianzhu Zhang, Zongtao Lu, Bingsen Qin, Hongyao Wang, Zhenghao Li, Song Duan, Yun Zheng, Yinze Zuo, Wei Yan & Jiujun Zhang.
As the global demand for sustainable, large-scale energy storage escalates, zinc-ion batteries (ZIBs) have emerged as a highly promising "post-lithium" alternative due to their intrinsic safety, environmental benignity, and high theoretical capacity. However, the commercial deployment of ZIBs is currently bottlenecked by severe interfacial instabilities, including the uncontrolled growth of needle-like zinc dendrites, parasitic side reactions (such as corrosion and hydrogen evolution), and the dissolution of cathode materials.
A new, comprehensive review article published in the journal ENGINEERING Energy by researchers from the Institute of New Energy Materials and Engineering at Fuzhou University provides a critical analysis of how Atomic Layer Deposition (ALD) is poised to overcome these exact challenges.
ALD is a highly advanced vapor-phase deposition technique renowned for its sub-nanometer precision and unparalleled conformality, allowing for the layer-by-layer growth of atomic films on complex battery components. The review systematically details a monumental paradigm shift in ALD application for batteries: the field is moving away from the simple use of passive physical barriers and toward multifunctional coatings capable of actively regulating interfacial chemistry.
Key Highlights and Research Perspectives:
- Atomic-Scale Interface Engineering: ALD enables the creation of uniform, pinhole-free protective layers that physically isolate the reactive zinc metal anode from aqueous electrolytes. This highly conformal shielding severely suppresses parasitic corrosion and hydrogen evolution reactions (HERs) while mechanically blocking dendrite penetration.
- The Paradigm Shift to Active Regulation: The review highlights a critical transition from chemically inert "passive" barriers (like Al₂O₃ and TiO₂) to active, zincophilic interphases (like ZnO, SnO₂, and Fe₂O₃). These advanced coatings lower nucleation overpotentials and actively induce preferred zinc deposition along specific crystallographic orientations, such as the Zn (002) basal plane, to fundamentally eliminate dendrite formation at the source.
- Cathode Stabilization: Beyond the anode, ALD acts as a protective exoskeleton for vulnerable high-capacity cathode materials, such as vanadium- and manganese-based oxides. ALD coatings actively suppress the dissolution of active species and prevent structural collapse. Furthermore, engineered heterostructures (like MnO@ZnO) generate built-in electric fields to significantly accelerate charge transfer kinetics.
- Functionalizing Separators: The application of ALD extends to battery separators, where metal-organic frameworks (MOFs, such as ZIF-8) can act as highly sophisticated molecular sieves. This structural regulation promotes selective and uniform Zn²⁺ ion transport while blocking bulky reactive species and free water, significantly extending battery longevity.
- Overcoming Scalability Hurdles: The authors present critical perspectives on moving ALD from lab-scale perfection to industrial viability. To resolve the "cost-scalability trade-off," the review suggests developing high-efficiency processes like Spatial ALD (S-ALD) and Roll-to-Roll (R2R) ALD, alongside hybrid ALD/Molecular Layer Deposition (MLD) coatings to improve mechanical flexibility.
By elucidating the complex structure-property relationships at the atomic scale, the Fuzhou University team provides a rational framework to bridge the gap between microscopic structural engineering and macroscopic battery performance. This research lays the fundamental groundwork for designing durable, high-performance aqueous energy storage systems tailored for the next generation of grid-scale applications.
Journal: ENGINEERING Energy
Read the full article for free: https://rdcu.be/frN5y
Cite this article: Huang, K., Zhang, S., Liu, Z. et al. Atomic layer deposition for advanced zinc-ion batteries. ENGINEERING Energy 20, 10722 (2026). https://doi.org/10.1007/s11708-026-1072-2
Journal
ENGINEERING Energy
Method of Research
News article
Article Title
Atomic layer deposition for advanced zinc-ion batteries
