Issue

Vol. 18 (2026)

A High-Performance Thermal Charging Cell with High Power Density and Long Runtime Enabled by Zn2+ and NH4+ Co-insertion

https://doi.org/10.1007/s40820-025-02011-9
Zhiwei Han
Jiangsu Key Laboratory of Electrochemical Energy Storage Technologies, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, People’s Republic of China
Shengliang Zhang
Jiangsu Key Laboratory of Electrochemical Energy Storage Technologies, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, People’s Republic of China
Helang Huang
Jiangsu Key Laboratory of Electrochemical Energy Storage Technologies, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, People’s Republic of China
Jing Wang
Jiangsu Key Laboratory of Electrochemical Energy Storage Technologies, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, People’s Republic of China
Hui Dou
Jiangsu Key Laboratory of Electrochemical Energy Storage Technologies, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, People’s Republic of China
Tianran Zhang
College of Material Science and Opto‑Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
Xiaogang Zhang
Jiangsu Key Laboratory of Electrochemical Energy Storage Technologies, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, People’s Republic of China

Corresponding Author: Xiaogang Zhang

azhangxg@nuaa.edu.cn

Nano-Micro Letters, Vol. 18 (2026), Article Number: 173

Abstract

Zn-based thermal charging devices, utilizing the synergistic effect of ion thermoextraction and thermodiffusion, are able to efficiently convert thermal energy into electrical energy and storage in the devices, making them a highly promising technology for low-grade heat recovery and utilization. However, the low output power density and energy conversion efficiency resulted by the slow diffusion kinetics of Zn2+ hinder their development. Herein, we present a high-performance thermal charging cell design using Zn2+/NH4+ hybrid ion electrolyte, which not only maintains the high output voltage of the Zn-based thermoelectric system, but also significantly enhances the output power density due to the fast diffusion kinetics of NH4+. Based on this strategy, the thermal charging cell displays a high thermopower of 12.5 mV K−1 and an excellent normalized power density of 19.6 mW m−2 K−2 at a temperature difference of 35 K. The Carnot-relative efficiency is as high as 12.74%. Moreover, it can operate continuously for over 72 h when the temperature difference persists, achieving a balance between thermoelectric conversion and output. This work provides a simple and effective strategy for the design of high-performance thermal charging cells for low-grade heat conversion and utilization.


Highlights:
1 The hybrid ion system strategically combines the high-voltage characteristics of Zn2+ redox with the exceptionally fast kinetics of NH4+, significantly boosting thermoelectric performance for low-grade heat harvesting.
2 The Zn2+/NH4+ co-insertion/thermoextraction mechanism is elucidated, where NH4+ exhibits exceptionally fast migration due to its unique hydrogen bonding diffusion behavior.
3 The device achieves a record 19.6 mW m⁻2 K⁻2 normalized power density with 72 h continuous operation, demonstrating strong application potential

Keywords

Thermal charging cells Zn2 /NH4 hybrid ions Low-grade heat conversion and storage High power density Hydrated V2O5
Han, Zhiwei, Shengliang Zhang, Helang Huang, Jing Wang, Hui Dou, Tianran Zhang, and Xiaogang Zhang. 2026. “A High-Performance Thermal Charging Cell With High Power Density and Long Runtime Enabled by Zn2+ and NH4+ Co-Insertion”. Nano-Micro Letters 18 (January):173. https://doi.org/10.1007/s40820-025-02011-9.
Download Citation
Endnote/Zotero/Mendeley (RIS)
BibTeX
References
  1. Y. Wang, L. Yang, X.-L. Shi, X. Shi, L. Chen, M.S. Dargusch, J. Zou, Z.-G. Chen, Flexible thermoelectric materials and generators: challenges and innovations. Adv. Mater. 31(29), 1807916 (2019). https://doi.org/10.1002/adma.201807916
  2. L. Zhang, X.-L. Shi, Y.-L. Yang, Z.-G. Chen, Flexible thermoelectric materials and devices: from materials to applications. Mater. Today 46, 62–108 (2021). https://doi.org/10.1016/j.mattod.2021.02.016
  3. X. Lu, Z. Mo, Z. Liu, Y. Hu, C. Du, L. Liang, G. Chen, Robust, efficient, and recoverable thermocells with zwitterion-boosted hydrogel electrolytes for energy-autonomous and wearable sensing. Angew. Chem. Int. Ed. 63(29), e202405357 (2024). https://doi.org/10.1002/anie.202405357
  4. P. Zhao, W. Xue, Y. Zhang, S. Zhi, X. Ma et al., Plasticity in single-crystalline Mg3Bi2 thermoelectric material. Nature 631(8022), 777–782 (2024). https://doi.org/10.1038/s41586-024-07621-8
  5. Z. Wu, S. Zhang, Z. Liu, E. Mu, Z. Hu, Thermoelectric converter: strategies from materials to device application. Nano Energy 91, 106692 (2022). https://doi.org/10.1016/j.nanoen.2021.106692
  6. J. He, T.M. Tritt, Advances in thermoelectric materials research: looking back and moving forward. Science 357(6358), eaak9997 (2017). https://doi.org/10.1126/science.aak9997
  7. Y. Xu, Z. Li, L. Wu, H. Dou, X. Zhang, Solvation engineering via fluorosurfactant additive toward boosted lithium-ion thermoelectrochemical cells. Nano-Micro Lett. 16(1), 72 (2024). https://doi.org/10.1007/s40820-023-01292-2
  8. X. Qian, Z. Ma, Q. Huang, H. Jiang, R. Yang, Thermodynamics of ionic thermoelectrics for low-grade heat harvesting. ACS Energy Lett. 9(2), 679–706 (2024). https://doi.org/10.1021/acsenergylett.3c02448
  9. J. Duan, B. Yu, L. Huang, B. Hu, M. Xu et al., Liquid-state thermocells: opportunities and challenges for low-grade heat harvesting. Joule 5(4), 768–779 (2021). https://doi.org/10.1016/j.joule.2021.02.009
  10. S. Sun, M. Li, X.-L. Shi, Z.-G. Chen, Advances in ionic thermoelectrics: from materials to devices. Adv. Energy Mater. 13(9), 2203692 (2023). https://doi.org/10.1002/aenm.202203692
  11. Y. Zhu, C.-G. Han, J. Chen, L. Yang, Y. Ma et al., Ultra-high performance of ionic thermoelectric-electrochemical gel cells for harvesting low grade heat. Energy Environ. Sci. 17(12), 4104–4114 (2024). https://doi.org/10.1039/d4ee01150c
  12. M. Yang, Y. Hu, X. Wang, H. Chen, J. Yu, W. Li, R. Li, F. Yan, Chaotropic effect-boosted thermogalvanic ionogel thermocells for all-weather power generation. Adv. Mater. 36(16), e2312249 (2024). https://doi.org/10.1002/adma.202312249
  13. C.-G. Han, X. Qian, Q. Li, B. Deng, Y. Zhu et al., Giant thermopower of ionic gelatin near room temperature. Science 368(6495), 1091–1098 (2020). https://doi.org/10.1126/science.aaz5045
  14. Y. Xu, Z. Li, S. Li, S. Zhang, X. Zhang, Reversibly tuning thermopower enabled by phase-change electrolytes for low-grade heat harvesting. Energy Environ. Sci. 18(2), 750–761 (2025). https://doi.org/10.1039/d4ee03351e
  15. B. Yu, J. Duan, H. Cong, W. Xie, R. Liu et al., Thermosensitive crystallization-boosted liquid thermocells for low-grade heat harvesting. Science 370(6514), 342–346 (2020). https://doi.org/10.1126/science.abd6749
  16. B. Chen, Q. Chen, S. Xiao, J. Feng, X. Zhang et al., Giant negative thermopower of ionic hydrogel by synergistic coordination and hydration interactions. Sci. Adv. 7(48), eabi7233 (2021). https://doi.org/10.1126/sciadv.abi7233
  17. Q. Yan, M.G. Kanatzidis, High-performance thermoelectrics and challenges for practical devices. Nat. Mater. 21(5), 503–513 (2022). https://doi.org/10.1038/s41563-021-01109-w
  18. Z. Li, Y. Xu, X. Zhang, Progresses and insights of thermoelectrochemical devices for low-grade heat harvesting: from mechanisms, materials to devices. EnergyChem 6(5), 100136 (2024). https://doi.org/10.1016/j.enchem.2024.100136
  19. Y. Liu, S. Zhang, Y. Zhou, M.A. Buckingham, L. Aldous, P.C. Sherrell, G.G. Wallace, G. Ryder, S. Faisal, D.L. Officer, S. Beirne, J. Chen, Advanced wearable thermocells for body heat harvesting. Adv. Energy Mater. 10(48), 2002539 (2020). https://doi.org/10.1002/aenm.202002539
  20. Z. Li, Y. Xu, L. Wu, H. Dou, X. Zhang, Microstructural engineering of hydrated vanadium pentoxide for boosted zinc ion thermoelectrochemical cells. J. Mater. Chem. A 10(40), 21446–21455 (2022). https://doi.org/10.1039/d2ta05882k
  21. Z. Li, Y. Xu, L. Wu, Y. An, Y. Sun et al., Zinc ion thermal charging cell for low-grade heat conversion and energy storage. Nat. Commun. 13(1), 132 (2022). https://doi.org/10.1038/s41467-021-27755-x
  22. Z. Li, Y. Xu, L. Wu, J. Cui, H. Dou et al., Enabling giant thermopower by heterostructure engineering of hydrated vanadium pentoxide for zinc ion thermal charging cells. Nat. Commun. 14(1), 6816 (2023). https://doi.org/10.1038/s41467-023-42492-z
  23. J. Cui, Z. Li, Y. Xu, Z. Han, S. Li et al., Zinc-iodine thermal charging cell engineered by cost-efficient electrolytes for low-grade heat harvesting. J. Power. Sources 602, 234325 (2024). https://doi.org/10.1016/j.jpowsour.2024.234325
  24. P. Ruan, S. Liang, B. Lu, H.J. Fan, J. Zhou, Design strategies for high-energy-density aqueous zinc batteries. Angew. Chem. Int. Ed. 61(17), e202200598 (2022). https://doi.org/10.1002/anie.202200598
  25. Y. Kim, Y. Park, M. Kim, J. Lee, K.J. Kim et al., Corrosion as the origin of limited lifetime of vanadium oxide-based aqueous zinc ion batteries. Nat. Commun. 13(1), 2371 (2022). https://doi.org/10.1038/s41467-022-29987-x
  26. T. Wang, S. Li, X. Weng, L. Gao, Y. Yan, N. Zhang, X. Qu, L. Jiao, Y. Liu, Ultrafast 3D hybrid-ion transport in porous V2O5 cathodes for superior-rate rechargeable aqueous zinc batteries. Adv. Energy Mater. 13(18), 2204358 (2023). https://doi.org/10.1002/aenm.202204358
  27. M. Zhou, X. Huang, H. Li, X. Duan, Q. Zhao, T. Ma, Hydrogen bonding chemistry in aqueous ammonium ion batteries. Angew. Chem. Int. Ed. 63(46), e202413354 (2024). https://doi.org/10.1002/anie.202413354
  28. G. Liang, Y. Wang, Z. Huang, F. Mo, X. Li, Qi. Yang, D. Wang, H. Li, S. Chen, C. Zhi, Initiating hexagonal MoO3 for superb-stable and fast NH4+ storage based on hydrogen bond chemistry. Adv. Mater. 32(14), 1907802 (2020). https://doi.org/10.1002/adma.201907802
  29. S. Dong, W. Shin, H. Jiang, X. Wu, Z. Li et al., Ultra-fast NH4+ storage: strong H bonding between NH4+ and bi-layered V2O5. Chem 5(6), 1537–1551 (2019). https://doi.org/10.1016/j.chempr.2019.03.009
  30. A. Roy, M. Sotoudeh, S. Dinda, Y. Tang, C. Kübel et al., Improving rechargeable magnesium batteries through dual cation co-intercalation strategy. Nat. Commun. 15(1), 492 (2024). https://doi.org/10.1038/s41467-023-44495-2
  31. Y. Wang, C. Wang, X. Yi, Y. Hu, L. Wang et al., Hybrid Mg/Li-ion batteries enabled by Mg2+/Li+ co-intercalation in VS4 nanodendrites. Energy Storage Mater. 23, 741–748 (2019). https://doi.org/10.1016/j.ensm.2019.06.001
  32. Y. Chen, Z. Song, Y. Lv, L. Gan, M. Liu, NH4+-modulated cathodic interfacial spatial charge redistribution for high-performance dual-ion capacitors. Nano-Micro Lett. 17(1), 117 (2025). https://doi.org/10.1007/s40820-025-01660-0
  33. P. Liu, Z. Song, Q. Huang, L. Miao, Y. Lv et al., Multi-H-bonded self-assembled superstructures for ultrahigh-capacity and ultralong-life all-organic ammonium-ion batteries. Energy Environ. Sci. 18(11), 5397–5406 (2025). https://doi.org/10.1039/d5ee00823a
  34. Z. Song, Q. Huang, Y. Lv, L. Gan, M. Liu, Multi-N-heterocycle donor-acceptor conjugated amphoteric organic superstructures for superior zinc batteries. Angew. Chem. Int. Ed. 64(6), e202418237 (2025). https://doi.org/10.1002/anie.202418237
  35. S. Li, X. Zhao, T. Wang, J. Wu, X. Xu, P. Li, X. Ji, H. Hou, X. Qu, L. Jiao, Y. Liu, Unraveling the “gap-filling” mechanism of multiple charge carriers in aqueous Zn-MoS2 batteries. Angew. Chem. Int. Ed. 63(11), e202320075 (2024). https://doi.org/10.1002/anie.202320075
  36. Z. Han, J. Cui, J. Wang, H. Dou, S. Zhang, X. Zhang, Ammonium-ion thermal charging supercapacitors for low-grade heat conversion and storage. Chem. Eng. J. 499, 156415 (2024). https://doi.org/10.1016/j.cej.2024.156415
  37. B. Yan, L. Liao, Y. You, X. Xu, Z. Zheng, Z. Shen, J. Ma, L. Tong, T. Yu, Single-crystalline V2O5 ultralong nanoribbon waveguides. Adv. Mater. 21(23), 2436–2440 (2009). https://doi.org/10.1002/adma.200803684
  38. Y. Dai, C. Zhang, J. Li, X. Gao, P. Hu, C. Ye, H. He, J. Zhu, W. Zhang, R. Chen, W. Zong, F. Guo, I.P. Parkin, D.J.L. Brett, P.R. Shearing, L. Mai, G. He, Inhibition of vanadium cathodes dissolution in aqueous Zn-ion batteries. Adv. Mater. 36(14), 2310645 (2024). https://doi.org/10.1002/adma.202310645
  39. Z. Li, Y. Xu, J. Cui, H. Dou, X. Zhang, High-efficiency zinc thermal charging supercapacitors enabled by hierarchical porous carbon electrodes. J. Power. Sources 555, 232386 (2023). https://doi.org/10.1016/j.jpowsour.2022.232386
  40. Z. Hu, S. Chang, C. Cheng, C. Sun, J. Liu et al., Calcium-ion thermal charging cell for advanced energy conversion and storage. Energy Storage Mater. 58, 353–361 (2023). https://doi.org/10.1016/j.ensm.2023.03.037
  41. T. Meng, Y. Xuan, X. Zhang, A thermally chargeable hybrid supercapacitor with high power density for directly converting heat to electricity. ACS Appl. Energy Mater. 4(6), 6055–6061 (2021). https://doi.org/10.1021/acsaem.1c00905
  42. Y. Li, Q. Li, X. Zhang, B. Deng, C. Han, W. Liu, 3D hierarchical electrodes boosting ultrahigh power output for gelatin-KCl-FeCN4−/3− ionic thermoelectric cells. Adv. Energy Mater. 12(14), 2103666 (2022). https://doi.org/10.1002/aenm.202103666
  43. C.-G. Han, Y.-B. Zhu, L. Yang, J. Chen, S. Liu et al., Remarkable high-temperature ionic thermoelectric performance induced by graphene in gel thermocells. Energy Environ. Sci. 17(4), 1559–1569 (2024). https://doi.org/10.1039/d3ee03818a
  44. H. Im, T. Kim, H. Song, J. Choi, J.S. Park et al., High-efficiency electrochemical thermal energy harvester using carbon nanotube aerogel sheet electrodes. Nat. Commun. 7, 10600 (2016). https://doi.org/10.1038/ncomms10600
  45. Q. Zong, Y. Zhuang, C. Liu, Q. Kang, Y. Wu, J. Zhang, J. Wang, D. Tao, Q. Zhang, G. Cao, Dual effects of metal and organic ions co-intercalation boosting the kinetics and stability of hydrated vanadate cathodes for aqueous zinc-ion batteries. Adv. Energy Mater. 13(31), 2301480 (2023). https://doi.org/10.1002/aenm.202301480
  46. F. Ye, R. Pang, C. Lu, Q. Liu, Y. Wu, R. Ma, L. Hu, Reversible ammonium ion intercalation/de-intercalation with crystal water promotion effect in layered VOPO4⋅2H2O. Angew. Chem. Int. Ed. 135(24), e202303480 (2023). https://doi.org/10.1002/ange.202303480
  47. D. Yu, Z. Wei, X. Zhang, Y. Zeng, C. Wang, G. Chen, Z.X. Shen, F. Du, Boosting Zn2+ and NH4+ storage in aqueous media via in situ electrochemical induced VS2/VOx heterostructures. Adv. Funct. Mater. 31(11), 2008743 (2021). https://doi.org/10.1002/adfm.202008743
  48. J. Li, K. McColl, X. Lu, S. Sathasivam, H. Dong et al., Multi-scale investigations of δ-Ni0.25V2O5·nH2O cathode materials in aqueous zinc-ion batteries. Adv. Energy Mater. 10(15), 2000058 (2020). https://doi.org/10.1002/aenm.202000058
  49. X. Chen, H. Zhang, J.-H. Liu, Y. Gao, X. Cao et al., Vanadium-based cathodes for aqueous zinc-ion batteries: mechanism, design strategies and challenges. Energy Storage Mater. 50, 21–46 (2022). https://doi.org/10.1016/j.ensm.2022.04.040
  50. S. Liu, H. Zhu, B. Zhang, G. Li, H. Zhu, Y. Ren, H. Geng, Y. Yang, Qi. Liu, C.C. Li, Tuning the kinetics of zinc-ion insertion/extraction in V2O5 by in situ polyaniline intercalation enables improved aqueous zinc-ion storage performance. Adv. Mater. 32(26), 2001113 (2020). https://doi.org/10.1002/adma.202001113
  51. X. Zhang, H. Wei, B. Ren, J. Jiang, G. Qu, J. Yang, G. Chen, H. Li, C. Zhi, Z. Liu, Unlocking high-performance ammonium-ion batteries: activation of in-layer channels for enhanced ion storage and migration. Adv. Mater. 35(40), e2304209 (2023). https://doi.org/10.1002/adma.202304209
  52. T. Zhai, H. Liu, H. Li, X. Fang, M. Liao, L. Li, H. Zhou, Y. Koide, Y. Bando, D. Golberg, Centimeter-long V2O5 nanowires: from synthesis to field-emission, electrochemical, electrical transport, and photoconductive properties. Adv. Mater. 22(23), 2547–2552 (2010). https://doi.org/10.1002/adma.200903586
  53. L. Xing, H. Chen, X. Wen, W. Zhou, K. Xiang, High performance of Co-doped V2O5 cathode material in V2O5-saturated (NH4)2SO4 electrolyte for ammonium ion battery. J. Alloys Compd. 925, 166652 (2022). https://doi.org/10.1016/j.jallcom.2022.166652
  54. T. Sun, Q. Nian, X. Ren, Z. Tao, Hydrogen-bond chemistry in rechargeable batteries. Joule 7(12), 2700–2731 (2023). https://doi.org/10.1016/j.joule.2023.10.010
Read More
Author biographies are not available.
Download this PDF file
PDF SUPPLEMENTARY FILE

Most read articles by the same author(s)

1 2 > >>