Revisiting the Enhancement Mechanism of Electrochemical Performance of Functional Atom-Doped Hard Carbon in Potassium-Ion Batteries

Abstract

Atomic doping is recognized as an effective strategy to enhance the electrochemical performance of hard carbon (HC) in potassium-ion batteries. However, the comprehension of its influence on microstructure remains inadequately understood. Here, we investigate the synergistic effect of structural evolution and performance changes of HC, while comprehensively analyzing the strengthening mechanism of N/S co-doping on potassium-ion storage. N/S can serve not only as active sites for electrochemical redox reactions, but also expand the carbon interlayer spacing while regulating electronic properties, thereby improving diffusion kinetics. Remarkably, the introduction of N/S can adjust the curvature of graphitic microcrystallites, promoting the formation of closed pore structures, which contributes to the pore-filling of quasi-metallic potassium clusters. Multidimensional characterization techniques confirmed the “adsorption-insertion/pore-filling” mechanism for potassium storage in HC. This work establishes a design theoretical framework aimed at enhancing electrochemical performance, offering a theoretical foundation and a selection methodology for the advancement of high-performance HC anode.

Keywords

biomass / hard carbon anode / potassium-ion batteries / energy storage mechanisms

References

[1] Y. Xu, Y. Du, H. Chen, et al., “Recent Advances in Rational Design for High-Performance Potassium-Ion Batteries,” Chemical Society Reviews 53, no. 13 (2024): 7202-7298.

[2] X. Yi, H. Fu, A. M. Rao, et al., “Safe Electrolyte for Long-Cycling Alkali-Ion Batteries,” Nature Sustainability 7, no. 3 (2024): 326-337.

[3] D. Zhang, H. Fu, X. Ma, et al., “Nonflammable Phosphate-Based Electrolyte for Safe and Stable Potassium Batteries Enabled by Optimized Solvation Effect,” Angewandte Chemie International Edition 136, no. 29 (2024): e202405153.

[4] J. Sun, F. Kang, D. Yan, et al., “Recent Progress in Using Covalent Organic Frameworks to Stabilize Metal Anodes for Highly-Efficient Rechargeable Batteries,” Angewandte Chemie International Edition 63, no. 28 (2024): e202406511.

[5] J. Liu, X. Shi, J. Liu, et al., “Crystallinity Degree of MoSe₂ Influencing Its Potassium-Ion Storage Performance,” Nano Research Energy 4, no. 1 (2025): e9120143.

[6] Y. Guo, S. Ji, J. Wang, et al., “Advancing Hard Carbon Anode for Sodium-Ion Batteries: Mechanisms and Optimization Strategies,” Nano Research Energy (2025), https://doi.org/10.26599/NRE.2025.9120165.

[7] Z. Zhu, Y. Men, W. Zhang, et al., “Versatile Carbon-Based Materials From Biomass for Advanced Electrochemical Energy Storage Systems,” Escience 4, no. 5 (2024): 100249.

[8] W. Cao, E. Zhang, J. Wang, et al., “Potato Derived Biomass Porous Carbon as Anode for Potassium Ion Batteries,” Electrochimica Acta 293 (2019): 364-370.

[9] J. P. Paraknowitsch and A. Thomas, “Doping Carbons Beyond Nitrogen: An Overview of Advanced Heteroatom Doped Carbons With Boron, Sulphur and Phosphorus for Energy Applications,” Energy & Environmental Science 6, no. 10 (2013): 2839-2855.

[10] L. Ma, J. Li, Z. Li, et al., “Ultra-Stable Potassium Ion Storage of Nitrogen-Doped Carbon Nanofiber Derived From Bacterial Cellulose,” Nanomaterials 11, no. 5 (2021): 1130.

[11] K. Zhao, C. Chen, M. La, et al., “O-Doping Configurations Reduce the Adsorption Energy Barrier of K-Ions to Improve the Electrochemical Performance of Biomass-Derived Carbon,” Micromachines 13, no. 5 (2022): 806.

[12] X. Chen, W. Zhou, J. Liu, et al., “Sulfur/Nitrogen/Oxygen Tri-Doped Carbon Nanospheres as an Anode for Potassium Ion Storage,” Journal of Energy Chemistry 77 (2023): 338-347.

[13] D. Nan, Z. Wu, Z. Lu, et al., “Facile Preparation of Heteroatom S Doped Dumbbell-Like Hard Carbon for Boosting Potassium-Ion Storage Capability,” Electrochimica Acta 465 (2023): 143019.

[14] Z. Zhu, F. Liang, Z. Zhou, et al., “Expanded Biomass-Derived Hard Carbon With Ultra-Stable Performance in Sodium-Ion Batteries,” Journal of Materials Chemistry A 6, no. 4 (2018): 1513-1522.

[15] X. Li, X. Zeng, T. Ren, et al., “The Transport Properties of Sodium-Ion in the Low Potential Platform Region of Oatmeal-Derived Hard Carbon for Sodium-Ion Batteries,” Journal of Alloys and Compounds 787 (2019): 229-238.

[16] Y. Zhang, H. Cheng, J. Liu, et al., “Laver-Derived Carbon as an Anode for SIBs With Excellent Electrochemical Performance,” International Journal of Electrochemical Science 15, no. 6 (2020): 5144-5153.

[17] Z. Tang, D. Jiang, Z. Fu, et al., “Regulating Pseudo-Graphitic Domain and Closed Pores to Facilitate Plateau Sodium Storage Capacity and Kinetics for Hard Carbon,” Small Methods 8, no. 12 (2024): 2400509.

[18] S. Zhou, Z. Tang, Z. Pan, et al., “Regulating Closed Pore Structure Enables Significantly Improved Sodium Storage for Hard Carbon Pyrolyzing at Relatively Low Temperature,” SusMat 2, no. 3 (2022): 357-367.

[19] Z. Tang, R. Zhang, H. Wang, et al., “Revealing the Closed Pore Formation of Waste Wood-Derived Hard Carbon for Advanced Sodium-Ion Battery,” Nature Communications 14, no. 1 (2023): 6024.

[20] G. Zhang, H. Gao, and D. Zhang, “Transformative Catalytic Carbon Conversion Enabling Superior Graphitization and Nanopore Engineering in Hard Carbon Anodes for Sodium-Ion Batteries,” Carbon Energy (2025), https://doi.org/10.1002/cey2.713.

[21] L. Kitsu Iglesias, E. N. Antonio, T. D. Martinez, et al., “Revealing the Sodium Storage Mechanisms in Hard Carbon Pores,” Advanced Energy Materials 13, no. 44 (2023): 2302171.

[22] G. Cheng, W. Zhang, W. Wang, et al., “Sulfur and Nitrogen Codoped Cyanoethyl Cellulose-Derived Carbon With Superior Gravimetric and Volumetric Capacity for Potassium Ion Storage,” Carbon Energy 4, no. 5 (2022): 986-1001.

[23] H. Tan, X. Du, R. Zhou, et al., “Rational Design of Microstructure and Interphase Enables High-Capacity and Long-Life Carbon Anodes for Potassium Ion Batteries,” Carbon 176 (2021): 383-389.

[24] T. Zhang, Z. Mao, X. Shi, et al., “Tissue-Derived Carbon Microbelt Paper: A High-Initial-Coulombic-Efficiency and Low-Discharge-Platform K⁺-Storage Anode for 4.5 V Hybrid Capacitors,” Energy & Environmental Science 15, no. 1 (2022): 158-168.

[25] C. Yuan, X. Liu, M. Jia, et al., “Facile Preparation of N-and O-Doped Hollow Carbon Spheres Derived From Poly(o-Phenylenediamine) for Supercapacitors,” Journal of Materials Chemistry A 3, no. 7 (2015): 3409-3415.

[26] Y. Li, C. Yang, F. Zheng, et al., “High Pyridine N-Doped Porous Carbon Derived From Metal-Organic Frameworks for Boosting Potassium-Ion Storage,” Journal of Materials Chemistry A 6, no. 37 (2018): 17959-17966.

[27] Y. He, J. Xue, M. Yang, et al., “Hollow Carbon Nanospheres for Capacitive-Dominated Potassium-Ion Storage,” Chemical Engineering Journal 409 (2021): 127383.

[28] Y. Qian, Y. Li, Z. Yi, et al., “Revealing the Double-Edged Behaviors of Heteroatom Sulfur in Carbonaceous Materials for Balancing K-Storage Capacity and Stability,” Advanced Functional Materials 31, no. 8 (2021): 2006875.

[29] Z. Qiu, K. X. Zhao, J. Liu, et al., “Nitrogen-Doped Mesoporous Carbon as an Anode Material for High Performance Potassium-Ion Batteries,” Electrochimica Acta 340 (2020): 135947.

[30] Y. Xu, C. Zhang, M. Zhou, et al., “Highly Nitrogen Doped Carbon Nanofibers With Superior Rate Capability and Cyclability for Potassium Ion Batteries,” Nature Communications 9, no. 1 (2018): 1720.

[31] S. Chen, K. Tang, F. Song, et al., “Porous Hard Carbon Spheres Derived From Biomass for High-Performance Sodium/Potassium-Ion Batteries,” Nanotechnology 33, no. 5 (2021): 055401.

[32] L. Zhong, W. Zhang, S. Sun, et al., “Engineering of the Crystalline Lattice of Hard Carbon Anodes Toward Practical Potassium-Ion Batteries,” Advanced Functional Materials 33, no. 8 (2023): 2211872.

[33] Y. Guo, Y. Feng, H. Li, et al., “Carbon Quantum Dots in Hard Carbon: An Approach to Achieving PIB Anodes With High Potassium Adsorption,” Carbon 189 (2022): 142-151.

[34] T. Huang, D. Peng, Z. Chen, et al., “Microstructures and Electrochemical Properties of Coconut Shell-Based Hard Carbons as Anode Materials for Potassium Ion Batteries,” New Carbon Materials 37, no. 6 (2022): 1125-1132.

[35] L. Xu, Z. Gong, C. Zhang, et al., “A Mushroom Derived Biomass Carbon as High-Stability Anode for Potassium Ion Battery,” Journal of Alloys and Compounds 934 (2023): 167820.

[36] D. Wang, Q. Wang, M. Tan, et al., “Biomass CQDs Derivate Carbon as High-Performance Anode for K-Ion Battery,” Journal of Alloys and Compounds 922 (2022): 166260.

[37] T. Zhu, B. Mai, P. Hu, et al., “Bagasse-Derived Hard Carbon Anode With an Adsorption-Intercalation Mechanism for High-Rate Potassium Storage,” ACS Applied Energy Materials 6, no. 4 (2023): 2370-2377.

[38] Z. Zhu, X. Li, Z. Zhang, et al., “N/S Codoping Modification Based on the Metal Organic Framework-Derived Carbon to Improve the Electrochemical Performance of Different Energy Storage Devices,” Journal of Energy Chemistry 74 (2022): 394-403.

[39] S. Huang, Z. Li, B. Wang, et al., “N-Doping and Defective Nanographitic Domain Coupled Hard Carbon Nanoshells for High Performance Lithium/Sodium Storage,” Advanced Functional Materials 28, no. 10 (2018): 1706294.

[40] D. Li, X. Ren, Q. Ai, et al., “Facile Fabrication of Nitrogen-Doped Porous Carbon as Superior Anode Material for Potassium-Ion Batteries,” Advanced Energy Materials 8, no. 34 (2018): 1802386.

[41] M. Yang, Q. Kong, W. Feng, et al., “N/O Double-Doped Biomass Hard Carbon Material Realizes Fast and Stable Potassium Ion Storage,” Carbon 176 (2021): 71-82.

[42] Z. Xu, S. Du, Z. Yi, et al., “Water Chestnut-Derived Slope-Dominated Carbon as a High-Performance Anode for High-Safety Potassium-Ion Batteries,” ACS Applied Energy Materials 3, no. 11 (2020): 11410-11417.

[43] Q. Wang, X. Zhu, Y. Liu, et al., “Rice Husk-Derived Hard Carbons as High-Performance Anode Materials for Sodium-Ion Batteries,” Carbon 127 (2018): 658-666.

[44] Y. Li, Y. Zhao, K. Chen, et al., “Rational Design of Cross-Linked N-Doped C-Sn Nanofibers as Free-Standing Electrodes Towards High-Performance Li-Ion Battery Anodes,” Acta Physico-Chimica Sinica 41, no. 3 (2024): 2305007.

[45] C. Yang, W. Zhong, Y. Liu, et al., “Regulating Solid Electrolyte Interphase Film on Fluorine-Doped Hard Carbon Anode for Sodium-Ion Battery,” Carbon Energy 6, no. 6 (2024): e503.

[46] X. Shi, H. Wang, Z. Xie, et al., “A Dual-Carbon Potassium-Ion Capacitor Enabled by Hollow Carbon Fibrous Electrodes With Reduced Graphitization,” Advanced Materials 36 (2024): 2406794.

[47] S. Tian, D. Guan, J. Lu, et al., “Synthesis of the Electrochemically Stable Sulfur-Doped Bamboo Charcoal as the Anode Material of Potassium-Ion Batteries,” Journal of Power Sources 448 (2020): 227572.

[48] D. Cao, X. Sun, Y. Li, et al., “Long-Cycling Sulfide-Based All-Solid-State Batteries Enabled by Electrochemo-Mechanically Stable Electrodes,” Advanced Materials 34, no. 24 (2022): 2200401.

[49] Z. Zhu, W. Zhong, Y. Zhang, et al., “Elucidating Electrochemical Intercalation Mechanisms of Biomass-derived Hard Carbon in Sodium-/Potassium-ion Batteries,” Carbon Energy 3, no. 4 (2021): 541-553.

[50] C. Chen, M. Wu, Y. Wang, et al., “Insights Into Pseudographite-Structured Hard Carbon With Stabilized Performance for High Energy K-Ion Storage,” Journal of Power Sources 444 (2019): 227310.

[51] M. Anji Reddy, M. Helen, A. Groß, et al., “Insight Into Sodium Insertion and the Storage Mechanism in Hard Carbon,” ACS Energy Letters 3, no. 12 (2018): 2851-2857.

[52] X. Li, X. Hu, L. Zhou, et al., “A S/N-Doped High-Capacity Mesoporous Carbon Anode for Na-Ion Batteries,” Journal of Materials Chemistry A 7, no. 19 (2019): 11976-11984.

[53] Z. Wang, X. Feng, Y. Bai, et al., “Probing the Energy Storage Mechanism of Quasi-Metallic Na in Hard Carbon for Sodium-Ion Batteries,” Advanced Energy Materials 11, no. 11 (2021): 2003854.

[54] G. Feher and A. F. Kip, “Electron Spin Resonance Absorption in Metals. I. Experimental,” Physical Review 98, no. 2 (1955): 337.

[55] K. Kawamura, “Electron Spin Resonance Behavior of Pitch-Based Carbons in the Heat Treatment Temperature Range of 1100-2000°C,” Carbon 36, no. 7-8 (1998): 1227-1230.

[56] E. Zhecheva, R. Stoyanova, J. M. Jiménez-Mateos, et al., “EPR Study on Petroleum Cokes Annealed at Different Temperatures and Used in Lithium and Sodium Batteries,” Carbon 40, no. 13 (2002): 2301-2306.

[57] Q. Li, J. Zhang, L. Zhong, et al., “Unraveling the Key Atomic Interactions in Determining the Varying Li/Na/K Storage Mechanism of Hard Carbon Anodes,” Advanced Energy Materials 12, no. 37 (2022): 2201734.

[58] Z. Yu, C. Chen, Q. Liu, et al., “Discovering the Pore-Filling of Potassium Ions in Hard Carbon Anodes: Revisit the Low-Voltage Region,” Energy Storage Materials 60 (2023): 102805.

RIGHTS & PERMISSIONS

2025 The Author(s). SusMat published by Sichuan University and John Wiley & Sons Australia, Ltd.