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
Nature’s blueprint for sustainable energy: biomass-derived materials pave the way for next-generation solid-state batteries
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Molecular structure
view moreCredit: Guowei Chen, Wenxu Zhuang & Tizazu Mekonnen.
As the global demand for high-energy-density, reliable, and safe energy storage escalates, solid-state batteries (SSBs) have emerged as superior alternatives to conventional batteries by replacing flammable liquid electrolytes with solid alternatives. However, the widespread commercialization of SSBs is currently impeded by formidable challenges, including high fabrication costs, sluggish ion kinetics across solid-solid interfaces, and environmental footprint concerns.
A comprehensive new review article published in ENGINEERING Energy demonstrates how integrating biomass-derived materials offers an innovative pathway to overcome these intrinsic limitations while simultaneously aligning with a circular bioeconomy and global carbon neutrality goals.
Conducted by researchers from Nanjing Forestry University and University of Waterloo, the study critically examines the transformative opportunity of repurposing natural structures for critical battery components. Biomass materials—encompassing organic matter from plants, agricultural residues, marine byproducts, and forestry waste—convert CO₂ and water into structurally sophisticated biopolymers like cellulose, lignin, and chitosan through photosynthesis. These carbon-neutral resources possess naturally hierarchical porosity, aligned channels, and functional groups that are difficult to replicate synthetically, making them ideal for advanced energy storage.
Key Research Highlights:
- Sustainability and Versatility:Biomass-derived materials provide sustainable, structurally tunable, and chemically versatile alternatives for key components in solid-state batteries (SSBs).
- Advanced Carbon Architectures: Bio-derived carbons, produced via methods like pyrolysis and hydrothermal carbonization, enable hierarchical porosity and controllable graphitization. This enhances efficient ion transport, catalytic activity, and mechanical buffering in electrode architectures.
- Enhanced Electrolyte Performance:Biopolymers such as cellulose, lignin, and chitosan serve as functional matrices for solid polymer and gel electrolytes, improving ionic conductivity and interfacial stability. Their intrinsic microstructures also serve as excellent templates for low-tortuosity ceramic electrolytes.
- Mitigation of Critical Challenges: The integration of bio-based binders, separators, and electrolyte additives effectively helps address and mitigate critical battery challenges, including dendrite growth, polysulfide shuttling, and interfacial degradation.
- Future Development and AI Integration: While key challenges remain regarding feedstock variability, impurity control, scalability, and performance trade-offs, the integration of artificial intelligence (AI) offers highly promising new materials design opportunities to accelerate development.
By synthesizing fundamental design principles and the latest progress in the field, this comprehensive review highlights how leveraging nature’s blueprint can accelerate the transition from laboratory concepts to industrially viable components, ultimately driving the development of high-performance, safe, and truly sustainable next-generation SSBs.
Journal: ENGINEERING Energy
Read the full article for free: https://rdcu.be/frN5e
Cite this article: Chen, G., Zhuang, W. & Mekonnen, T. Biomass-derived materials for next-generation solid-state batteries: From sustainable resources to advanced electrodes and electrolytes. ENG. Energy 20, 10789 (2026). https://doi.org/10.1007/s11708-026-1078-9
Journal
ENGINEERING Energy
Method of Research
News article
Article Title
Biomass-derived materials for next-generation solid-state batteries: From sustainable resources to advanced electrodes and electrolytes
Batteries lose lithium in the current collector
Precise 3D maps of arbitrary elements
The copper current collector is a thin copper foil that serves as a substrate for the anode and collects electrons to lead them to the negative terminal. In lithium-metal batteries, lithium can diffuse into the copper current collector during the charge and discharge cycle. “However, it was previously unclear where the lithium ions accumulate,” explains Li. “It is difficult to detect lithium in copper because of a lack of analytical methods for tracing highly reactive and lightweight lithium.”
The research team utilized atom probe tomography, which allows the precise, three-dimensional mapping of any element with sub-nanometer resolution. This revealed that, after just one charge/discharge cycle, lithium is initially incorporated at the grain boundary and boundary junction of the copper foil. After three cycles, the surface of the copper foil becomes nanocrystalline and oxidized. The resulting defects further bind lithium and oxygen beneath the surface, leading to degradation of the copper current collector.
Lithium loss in new battery technology previously overlooked
“All this information is important for understanding how the current collector influences the performance of lithium batteries of the future,” explains Li; lithium-metal batteries (LMBs), and recently zero-excess or anode-free LMBs are seen to be the next significant steps on the path toward even higher energy densities. These far surpass the currently prevailing lithium-ion technology. “The general assumption about zero-excess LMBs is that lithium does not diffuse into or interact with the copper current collector,” says Li. “the loss of lithium to the copper collector has been largely overlooked until now, in discussions about the performance degradation of LMBs.”
Journal
Advanced Energy Materials
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Atomic-Scale Tracing of Lithium Trapped in Copper Current Collectors
Article Publication Date
10-Jul-2026
Stress-free magnesium anode breaks through to Ah-level pouch cell, paving way for commercial rechargeable magnesium batteries
Rechargeable magnesium batteries promise higher volumetric capacity and greater resource abundance than lithium-ion systems, yet their anodes have been crippled by native oxide layers and uneven stripping/plating that shorten cycle life and prevent scale-up. Researchers have now developed a simple protonated organic solvent treatment that removes the surface oxide, forms a functional magnesium ethoxide interlayer, and relieves surface stress while preserving the anode's original microstructure. The result: symmetric pouch cells that cycle for over 4,000 hours and the world's first 1.07 ampere-hour (Ah) multilayer magnesium pouch cell, marking a critical step toward commercial-scale rechargeable magnesium batteries.
The native oxide film (MgO and Mg(OH)₂) that forms on magnesium metal in air or during processing repeatedly ruptures and reforms during battery operation, causing non-uniform deposition, low coulombic efficiency, and rapid failure. Traditional approaches — mechanical grinding, polishing, and acid treatments — either introduce stress concentrations and defects into the microstructure or remain confined to small-format coin cells. Grinding-induced stress layers can reach 30 micrometers in depth, creating preferential corrosion sites that accelerate degradation. Meanwhile, acid-based methods have struggled to simultaneously address interface chemistry and bulk microstructure in a way that scales to practical cell formats. Based on these challenges, a practical approach capable of stabilizing both the anode interface and the microstructure in a scalable manner is urgently needed.
Researchers from Chongqing University and Xiamen University report (DOI: 10.1016/j.esci.2026.100609) in eScience (online June 19, 2026) that a protonated organic solvent treatment — using hydrochloric acid and ethanol — transforms the magnesium anode surface by replacing the native oxide layer with a magnesium ethoxide (Mg(C₂H₅O)₂) interlayer while preserving a stress-free microstructure. This dual modification enables uniform magnesium stripping and plating, delivering unprecedented cycling stability and the first demonstration of Ah-level performance in a multilayer pouch cell.
The team systematically screened acids and solvents and selected hydrochloric acid in ethanol to treat large-format magnesium foils — achieving batch-processed anodes up to 150 cm × 10 cm in size. Transmission electron microscopy revealed that the native 4.6 nm MgO layer was replaced by an 8.5 nm magnesium ethoxide layer. Nuclear magnetic resonance spectroscopy confirmed the Mg–O–C bonding, while electron backscatter diffraction showed that the treated anodes retained a stress-free microstructure— in stark contrast to mechanically ground anodes, which exhibited stress-concentrated layers approximately 30 μm deep with an average kernel average misorientation (KAM) value of 2.05 versus only 0.18 for the treated anodes.
During cycling, the time-of-flight secondary ion mass spectrometry (TOF-SIMS) showed magnesium ethoxide interlayer decomposes and participates in forming a solid electrolyte interphase (SEI) with significantly lower levels of passivating MgO and Mg(OH)₂ components. Density functional theory (DFT) calculations further revealed that magnesium atoms preferentially strip and plate at grain boundaries, where the dissociation energy is 0.73 eV compared to 1.58 eV on grain interiors, and adsorption energy is −1.24 eV versus −0.85 eV. This grain-boundary-guided mechanism, combined with the low-passivation SEI, enabled uniform deposition without dendrites.
“The key insight here is that you can't just fix the surface — you have to address the microstructure underneath,” the authors said. “Our treatment does both in one simple step: it clears away the problematic oxide, builds a functional interlayer that evolves into a better SEI, and leaves the metal's grain structure intact so that grain boundaries can do their job as natural nucleation sites. We were surprised to see symmetric pouch cells run for over 4,000 hours, and building a 1.07 Ah multilayer cell — the largest reported for magnesium — really convinced us this approach can scale.”
This work directly addresses the manufacturing bottleneck that has kept magnesium batteries in the laboratory. The simple immersion-based treatment is compatible with roll-to-roll processing, making it industrially viable for large-scale anode production. When paired with Chevrel-phase Mo₆S₈ cathodes, the treated anodes delivered 1,500 cycles with 79.8% capacity retention at 0.5 C — far outperforming ground anodes which retained only 14.4%. The Ah-level pouch cell, stacking five cathode sheets and three magnesium foils, achieved 1.07 Ah initial capacity and maintained stable operation over 50 cycles. Beyond grid storage and electric transportation, this breakthrough could accelerate the commercialization of rechargeable magnesium batteries as a safer, more sustainable alternative to lithium-ion systems.
Reference
Title of original paper | Design of a stress-free magnesium anode with a functional interface layer towards practical Ah-level pouch cell |
Journal | eScience eScience – a Golden Open Access journal cooperated with KeAi and published online at ScienceDirect. eScience is founded by Nankai University (China) in 2021 and aims to publish high quality academic papers on the latest and finest scientific and technological research in interdisciplinary fields related to energy, electrochemistry, electronics, and environment. eScience provides insights, innovation and imagination for these fields by built consecutive discovery and invention. Now eScience has been indexed by SCIE, EI, CAS, Scopus and DOAJ. Its impact factor is 52.9, which is ranked first in the field of electrochemistry. |
DOI | 10.1016/j.esci.2026.100609 |
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Media contact
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Email: eScience@nankai.edu.cn
The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 200 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).
Journal
eScience
Article Title
Design of a stress-free magnesium anode with a functional interface layer towards practical Ah-level pouch cell
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