High‐Entropy Layered Oxide Cathode Enabling High‐Rate for Solid‐State Sodium‐Ion Batteries (1).pdf
Vol.:(0123456789) 1 3   e-ISSN 2150-5551       CN 31-2103/TB ARTICLE Cite as Nano-Micro Lett.            (2024) 16:10  Received: 28 June 2023  Accepted: 28 September 2023  © The Author(s) 2023 https://doi.org/10.1007/s40820-023-01232-0 High‑Entropy Layered Oxide Cathode Enabling  High‑Rate for Solid‑State Sodium‑Ion Batteries Tianxun Cai1,3, Mingzhi Cai2, Jinxiao Mu1,3, Siwei Zhao2, Hui Bi1, Wei Zhao1,4,  Wujie Dong1, Fuqiang Huang1,2,3 * HIGHLIGHTS •	 High-entropy oxides O3-Na0.95Li0.06Ni0.25Cu0.05Fe0.15Mn0.49O2 cathode constructed by compatible radius and different Fermi level  ions was designed for solid-state Na-ion batteries. •	 Na0.95Li0.06Ni0.25Cu0.05Fe0.15Mn0.49O2 cathode exhibits high-rate performance, air stability and electrochemically thermal stability. •	 A series of characterizations were performed to explore energy storage mechanism of ­Na0.95Li0.06Ni0.25Cu0.05Fe0.15Mn0.49O2. ABSTRACT  Na-ion O3-type layered oxides are  prospective cathodes for Na-ion batteries due to  high energy density and low-cost. Nevertheless,  such cathodes usually suffer from phase transi- tions, sluggish kinetics and air instability, making  it difficult to achieve high performance solid-state  sodium-ion batteries. Herein, the high-entropy  design and Li doping strategy alleviate lattice  stress and enhance ionic conductivity, achieving  high-rate performance, air stability and electrochemically thermal stability for ­Na0.95Li0.06Ni0.25Cu0.05Fe0.15Mn0.49O2. This cathode delivers  a high reversible capacity (141 mAh ­g−1 at 0.2C), excellent rate capability (111 mAh ­g−1 at 8C, 85 mAh ­g−1 even at 20C), and long-term  stability (over 85% capacity retention after 1000 cycles), which is attributed to a rapid and reversible O3–P3 phase transition in regions  of low voltage and suppresses phase transition. Moreover, the compound remains unchanged over seven days and keeps thermal stability  until 279 ℃. Remarkably, the polymer solid-state sodium battery assembled by this cathode provides a capacity of 92 mAh ­g−1 at 5C and  keeps retention of 96% after 400 cycles. This strategy inspires more rational designs and could be applied to a series of O3 cathodes to  improve the performance of solid-state Na-ion batteries.  KEYWORDS  High-entropy; High-rate performance; Li–TM interaction; Air stability; O3 layered oxide cathode  *	 Fuqiang Huang, huangfq@mail.sic.ac.cn 1	 State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences,  Shanghai 200050, People’s Republic of China 2	 State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University,  Beijing 100871, People’s Republic of China 3	 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049,  People’s Republic of China 4	 Zhongke Institute of Strategic Emerging Materials, Yixing 214213, Jiangsu, People’s Republic of China 	 Nano-Micro Lett.           (2024) 16:10     10   Page 2 of 12 https://doi.org/10.1007/s40820-023-01232-0 © The authors 1  Introduction Sodium-ion batteries (SIBs) have attracted huge attention  as a prospective alternative to lithium-ion batteries (LIBs),  particularly in large-scale energy storage because of the  abundance and low price of Na resources, as well as simi- lar chemical properties to the commercial LIB [1–3]. The  Na-ion layered oxide materials, ­NaxTMO2 have consider- able potential as cathode materials for NIBs owing to the  notable benefits including high energy density, facile pro- duction and cost-effectiveness. Designing cathode materi- als possessing high Na content and rapid diffusion kinetics  is a crucial aspect in achieving commercial application.  Compared with P2-type cathodes, O3-type materials pos- sess higher sodium content, rendering them desirable to  couple with sodium-free anode [4, 5]. Nevertheless, the  potential for their actual application is constrained by  some significant limitations, namely, the complex phase  transitions, the sluggish ­Na+ diffusion kinetics and the  inherent sensitivity to air. Layered O3-type ­NaxTMO2  displays more complex phase transitions in comparison  with its Li analogs due to larger ­Na+ ions associated with  charge ordering and the ordering arrangement between  ­Na+ and vacancies [5, 6]. The slower sodium-ion kinetics  of O3-type material is an inherent characteristic due to  its narrower spacing between sodium interlayers. In O3  framework, the migration of ­Na+ between octahedral sites  must pass via a tetrahedral site, resulting in a high energy  barrier owing to the difference in size between the large  Na-ion and confined tetrahedral voids [7, 8]. On the other  hand, in the presence of air, O3 materials experience the  generation of active Na on the surface. This process is  accompanied by the structure aberration and the oxidation  of transition metal ions within the bulk. The segregated Na  undergoes a fast reaction with ­H2O/CO2 in ambient air.  This reaction leads to the creation of NaOH or ­Na2CO3 on  the surface of active materials, hence causing the deterio- rated battery performance [7, 9, 10]. Therefore, searching  for a strategy to resolve these unfavorable factors is critical  for realizing high performance solid-state Na-ion batteries. Some investigations have demonstrated that the appro- priate element substitutions (such as ­Ti4+, ­Mg2+, ­Cu2+,  ­Al3+, ­Sn4+, ­Zn2+, etc.) considerably suppress the irrevers- ible phase transition and improve ­Na+ diffusion coefficient  of O3-type oxides [11–15]. However, in order to achieve  better performance, the O3-type material is still needed to  be optimized. High-entropy oxides (HEOs) have gained  significant attention in the realm of electrochemical energy  storage, owing to its distinctive structure and exceptional  performance [16–20]. HEOs are regarded as a stable solid  solution phase consisting of five or more elements in equi- molar or nearly equimolar ratios (each element content  is within the range of 5–35%) [21, 22]. Zhao et al. suc- cessfully prepared a high-entropy O3-type layered oxide  ­NaNi0.12Cu0.12Mg0.12Fe0.15Co0.15Mn0.1Ti0.1Sn0.1Sb0.04O2  cathode. The HEO cathode exhibited remarkable cycling  stability, with a capacity retention of 83% after 500 cycles  and enhanced rate performance, retaining 80% capacity  at 5C. Furthermore, the researchers also revealed that the  high-entropy structure can prolong the phase transition,  which is beneficial to improve the cycling stability of cath- ode materials [20]. Inspired by HEOs in electrochemical energy storage, we  designed a novel five-component layered HEO O3-Na0.95 Li0.06Ni0.25Cu0.05Fe0.15Mn0.49O2 as a cathode for SIBs, the  schematic diagram is shown in Fig. 1a. The HEO cathode  constructed by compatible radius and different Fermi level  ions is effective for preventing charge ordering and reduc- ing the electronic localization [12]. Meanwhile, ionic con- ductivity can be enhanced through disorder, which con- tributes to energetically favorable routes in high-entropy  lattices [23]. Owing to the poor overlap between Li: 1s  and O: 2p orbitals, the bonding between Li and O is pre- dominantly ionic, resulting in an improved interaction of  the TM center with oxygen orbitals and transfer of charge  from sodium to oxygen. The strength of the TM-O and  Na–O bonds for ­Na0.95Li0.06Ni0.25Cu0.05Fe0.15Mn0.49O2  enhances structure stability. Although ionic bonds are not  as strong as covalent bonds, they repair themselves when  broken. The combination of ionic and covalent bonds with  hardness and softness alleviates stress. Moreover, the ­Li+  and ­Cu2+ with low valence doping increases the valence  of manganese ions, which impedes the Jahn–Teller effect.  The introduction of Na vacancies decreases the tetrahedral  site energy via increased interlayer distance due to the  decreased shielding effect [7, 24]. In consequence, this HEO O3-type cathode exhibits excel- lent rate performance and keeps highly reversible structure  evolution during cycling, delivering a high reversible capac- ity of 111.4 mAh ­g−1 at 1600 mA ­g−1 and retaining capacity  of 83.2% after 500 cycles. Even at 4000 mA ­g−1, this HEO  	 Nano-Micro Lett.           (2024) 16:10     10   Page 10 of 12 https://doi.org/10.1007/s40820-023-01232-0 © The authors cycling and rate performance of ­Na0.95LNCFM PSE battery  is almost comparable to those of the Liquid battery, demon- strating a promising practical application of SIBs. 4  Conclusion In summary, we report a novel high-entropy O3-type  layered cathode for solid-state sodium-ion batteries. The  design of high-entropy structure and Li–TM interaction  alleviate lattice stress and enhance ionic conductivity,  enabling a rapid and reversible O3–P3 phase transition  at low voltage regions and suppressing phase transition,  thus leading to excellent rate and cycling performances.  Meanwhile, due to the strengthened ­TMO2 framework and  Na–O binding energy, ­Na0.95LNCFM exhibits remark- able air stability and thermal stability. The combination  of high-entropy and Li–TM interaction conceptions is  an effective strategy to regulate the phase evolution, air  stability and thermal stability. Therefore, we believe that  such strategy may also be extensively applied to a series  of cathodes to improve the performance of solid-state Na- ion batteries. Acknowledgements  This work was supported by National Natural  Science Foundation of China (52202327), Science and Technology  Commission of Shanghai Municipality (22ZR1471300), National  Science Foundation of China (Grant 51972326) and Youth Innova- tion Promotion Association CAS, Foundation Strengthening Pro- ject, and Program of Shanghai Academic Research Leader (Grant  22XD1424300). Funding  Open access funding provided by Shanghai Jiao Tong  University. Declarations  Conflict of interest  The authors declare no conflict of interest. They  have no known competing financial interests or personal relationships  that could have appeared to influence the work reported in this paper. Open Access   This article is licensed under a Creative Commons  Attribution 4.0 International License, which permits use, sharing,  adaptation, distribution and reproduction in any medium or format,  as long as you give appropriate credit to the original author(s) and  the source, provide a link to the Creative Commons licence, and  indicate if changes were made. The images or other third party  material in this article are included in the article’s Creative Com- mons licence, unless indicated otherwise in a credit line to the  material. If material is not included in the article’s Creative Com- mons licence and your intended use is not permitted by statutory  regulation or exceeds the permitted use, you will need to obtain  permission directly from the copyright holder. To view a copy of  this licence, visit http://​creat​iveco​mmons.​org/​licen​ses/​by/4.​0/. Supplementary Information  The online version contains  supplementary material available at https://​doi.​org/​10.​1007/​ s40820-​023-​01232-0. Fig. 5   Electrochemical performance of ­Na0.95LNCFM PSE battery. a Schematic illustration for ­Na0.95LNCFM PSE battery. b Rate performance.  Charge/discharge profiles at various rates. c, d Long-term cycling performance at 2C rate and at 5C rate Nano-Micro Lett.           (2024) 16:10 	 Page 11 of 12     10  1 3 References 	1.	 X.L. Deng, K.Y. Zou, R. Momen, P. Cai, J. Chen et al., High  content anion (S/Se/P) doping assisted by defect engineering  with fast charge transfer kinetics for high-performance sodium  ion capacitors. Sci. Bull. 66(18), 1858–1868 (2021). https://​ doi.​org/​10.​1016/j.​scib.​2021.​04.​042 	2.	 R. Usiskin, Y.X. Lu, J. Popovic, M. Law, P. Balaya et al., Fun- damentals, status and promise of sodium-based batteries. Nat.  Rev. Mater. 6(11), 1020–1035 (2021). https://​doi.​org/​10.​1038/​ s41578-​021-​00324-w 	3.	 Z. Guo, G. Qian, C. Wang, G. Zhang, R. Yin et al., Progress  in electrode materials for the industrialization of sodium-ion  batteries. Prog. Nat. Sci. Mater. 33, 1 (2022). https://​doi.​org/​ 10.​1016/j.​pnsc.​2022.​12.​003 	4.	 P.F. Wang, Y. You, Y.X. Yin, Y.G. Guo, Layered oxide cath- odes for sodium-ion batteries: phase transition, air stability,  and performance. Adv. Energy Mater. 8(8), 23 (2018). https://​ doi.​org/​10.​1002/​aenm.​20170​1912 	5.	 K. Kubota, S. Kumakura, Y. Yoda, K. Kuroki, S. Komaba,  Electrochemistry and solid-state chemistry of ­NaMeO2  (Me=3d transition metals). Adv. Energy Mater. 8(17), 40  (2018). https://​doi.​org/​10.​1002/​aenm.​20170​3415 	6.	 W. Zhu, J.C. Zhang, J.W. Luo, C.H. Zeng, H. Su et al., Ultra- fast non-equilibrium synthesis of cathode materials for li-ion  batteries. Adv. Mater. 35(2), 9 (2023). https://​doi.​org/​10.​1002/​ adma.​20220​8974 	7.	 X.G. Yuan, Y.J. Guo, L. Gan, X.A. Yang, W.H. He et al., A  universal strategy toward air-stable and high-rate ­O3 layered  oxide cathodes for na-ion batteries. Adv. Funct. Mater. 32(17),  11 (2022). https://​doi.​org/​10.​1002/​adfm.​20211​1466 	8.	 M.H. Han, E. Gonzalo, G. Singh, T. Rojo, A comprehensive  review of sodium layered oxides: powerful cathodes for na-ion  batteries. Energy Environ. Sci. 8(1), 81–102 (2015). https://​ doi.​org/​10.​1039/​c4ee0​3192j 	9.	 X.W. Li, X. Shen, J.M. Zhao, Y. Yang, Q.Q. Zhang et al.,  O3-NaFe((1/3−x))Ni(1/3)Mn(1/3)AlxO(2) cathodes with  improved air stability for na-ion batteries. ACS Appl. Mater.  Interfaces 13(28), 33015–33023 (2021). https://​doi.​org/​10.​ 1021/​acsami.​1c075​54 	10.	 F.X. Ding, Q.S. Meng, P.F. Yu, H.B. Wang, Y.S. Niu et al.,  Additive-free self-presodiation strategy for high-performance  na-ion batteries. Adv. Funct. Mater. 31(26), 9 (2021). https://​ doi.​org/​10.​1002/​adfm.​20210​1475 	11.	 Y.M. Li, Z.Z. Yang, S.Y. Xu, L.Q. Mu, L. Gu et al., Air-stable  copper-based P2-Na7/9Cu2/9Fe1/9Mn2/3O2 as a new positive  electrode material for sodium-ion batteries. Adv. Sci. 2(6), 7  (2015). https://​doi.​org/​10.​1002/​advs.​20150​0031 	12.	 P.F. Wang, H.R. Yao, X.Y. Liu, J.N. Zhang, L. Gu et al.,  Ti-substituted ­NaNi0.5Mn0.5−xTixO2 cathodes with reversible  O3–P3 phase transition for high-performance sodium-ion  batteries. Adv. Mater. 29(19), 7 (2017). https://​doi.​org/​10.​ 1002/​adma.​20170​0210 	13.	 X.Q. Huang, D.L. Li, H.J. Huang, X. Jiang, Z.H. Yang et al.,  Fast and highly reversible na+ intercalation/extraction in  zn/mg dual-doped P2-Na0.67MnO2 cathode material for  high-performance na-ion batteries. Nano Res. 14(10), 3531– 3537 (2021). https://​doi.​org/​10.​1007/​s12274-​021-​3715-2 	14.	 Y.X. Wang, L.G. Wang, H. Zhu, J. Chu, Y.J. Fang et al.,  Ultralow-strain zn-substituted layered oxide cathode with  suppressed P2–O2 transition for stable sodium ion storage.  Adv. Funct. Mater. 30(13), 9 (2020). https://​doi.​org/​10.​1002/​ adfm.​20191​0327 	15.	 H.R. Yao, P.F. Wang, Y. Gong, J.N. Zhang, X.Q. Yu et al.,  Designing air-stable O3-type cathode materials by combined  structure modulation for na-ion batteries. J. Am. Chem. Soc.  139(25), 8440–8443 (2017). https://​doi.​org/​10.​1021/​jacs.​ 7b051​76 	16.	 X.Y. Du, Y. Meng, H.Y. Yuan, D. Xiao, High-entropy sub- stitution: a strategy for advanced sodium-ion cathodes with  high structural stability and superior mechanical properties.  Energy Storage Mater. 56, 132–140 (2023). https://​doi.​org/​ 10.​1016/j.​ensm.​2023.​01.​010 	17.	 F. Fu, X. Liu, X.G. Fu, H.W. Chen, L. Huang et al., Entropy  and crystal-facet modulation of P2-type layered cathodes for  long-lasting sodium-based batteries. Nat. Commun. 13(1),  12 (2022). https://​doi.​org/​10.​1038/​s41467-​022-​30113-0 	18.	 L.B. Yao, P.C. Zou, C.Y. Wang, J.H. Jiang, L. Ma et al.,  High-entropy and superstructure-stabilized layered oxide  cathodes for sodium-ion batteries. Adv. Energy Mater.  12(41), 9 (2022). https://​doi.​org/​10.​1002/​aenm.​20220​1989 	19.	 F.X. Ding, C.L. Zhao, D.D. Xiao, X.H. Rong, H.B. Wang  et al., Using high-entropy configuration strategy to design  Na-ion layered oxide cathodes with superior electrochemi- cal performance and thermal stability. J. Am. Chem. Soc.  144(18), 8286–8295 (2022). https://​doi.​org/​10.​1021/​jacs.​ 2c023​53 	20.	 C.L. Zhao, F.X. Ding, Y.X. Lu, L.Q. Chen, Y.S. Hu, High- entropy layered oxide cathodes for sodium-ion batteries.  Angew. Chem. Int. Ed. 59(1), 264–269 (2020). https://​doi.​ org/​10.​1002/​anie.​20191​2171 	21.	 C.M. Rost, E. Sachet, T. Borman, A. Moballegh, E.C. Dickey  et al., Entropy-stabilized oxides. Nat. Commun. 6, 8 (2015).  https://​doi.​org/​10.​1038/​ncomm​s9485 	22.	 A. Sarkar, L. Velasco, D. Wang, Q.S. Wang, G. Talasila et al.,  High entropy oxides for reversible energy storage. Nat. Com- mun. 9, 9 (2018). https://​doi.​org/​10.​1038/​s41467-​018-​05774-5 	23.	 M. Botros, J. Janek, Embracing disorder in solid-state batter- ies. Science 378(6626), 1273–1274 (2022). https://​doi.​org/​10.​ 1126/​scien​ce.​adf33​83 	24.	 H.J. Wang, X. Gao, S. Zhang, Y. Mei, L.S. Ni et al., High- entropy na-deficient layered oxides for sodium-ion batteries.  ACS Nano 17, 12530 (2023). https://​doi.​org/​10.​1021/​acsna​no.​ 3c022​90 	25.	 S.Y. Zhang, Y.J. Guo, Y.N. Zhou, X.D. Zhang, Y.B. Niu et al.,  P3/O3 integrated layered oxide as high-power and long-life  cathode toward na-ion batteries. Small 17(10), 7 (2021).  https://​doi.​org/​10.​1002/​smll.​20200​7236 	26.	 J.Y. Hwang, S.M. Oh, S.T. Myung, K.Y. Chung, I. Belharouak  et al., Radially aligned hierarchical columnar structure as a  cathode material for high energy density sodium-ion batteries.  	 Nano-Micro Lett.           (2024) 16:10     10   Page 12 of 12 https://doi.org/10.1007/s40820-023-01232-0 © The authors Nat. Commun. 6, 9 (2015). https://​doi.​org/​10.​1038/​ncomm​ s7865 	27.	 P.F. Zhou, Z.N. Che, J. Liu, J.K. Zhou, X.Z. Wu et al., High- entropy P2/O3 biphasic cathode materials for wide-tempera- ture rechargeable sodium-ion batteries. Energy Storage Mater.  57, 618–627 (2023). https://​doi.​org/​10.​1016/j.​ensm.​2023.​03.​ 007 	28.	 L.X. Shen, Y. Jiang, Y.F. Liu, J.L. Ma, T.R. Sun et al., High- stability monoclinic nickel hexacyanoferrate cathode materials  for ultrafast aqueous sodium ion battery. Chem. Eng. J. 388, 9  (2020). https://​doi.​org/​10.​1016/j.​cej.​2020.​124228 	29.	 W.J. Dong, B. Ye, M.Z. Cai, Y.Z. Bai, M. Xie et al., Superwet- table high-voltage ­LiCOO2 for low- temperature lithium ion  batteries. ACS Energy Lett. 8(2), 881–888 (2023). https://​doi.​ org/​10.​1021/​acsen​ergyl​ett.​2c024​34 	30.	 C. Zeng, C. Duan, Z. Guo, Z. Liu, S. Dou et al., Ultrafastly  activated needle coke as electrode material for supercapaci- tors. Prog. Nat. Sci. Mater. Inter. 32(6), 786–792 (2022).  https://​doi.​org/​10.​1016/j.​pnsc.​2022.​10.​008 	31.	 Y.Y. Xie, G.L. Xu, H.Y. Che, H. Wang, K. Yang et al., Prob- ing thermal and chemical stability of ­NaxNi1/3Fe1/3Mn1/3O2  cathode material toward safe sodium-ion batteries. Chem. Mat.  30(15), 4909–4918 (2018). https://​doi.​org/​10.​1021/​acs.​chemm​ ater.​8b000​47 	32.	 H.R. Yao, X.G. Yuan, X.D. Zhang, Y.J. Guo, L.T. Zheng et al.,  Excellent air storage stability of na-based transition metal  oxide cathodes benefiting from enhanced na-o binding energy.  Energy Storage Mater. 54, 661–667 (2023). https://​doi.​org/​10.​ 1016/j.​ensm.​2022.​11.​005 	33.	 W.H. Zuo, J.M. Qiu, X.S. Liu, F.C. Ren, H.D. Liu et al., The  stability of p2-layered sodium transition metal oxides in ambi- ent atmospheres. Nat. Commun. 11(1), 12 (2020). https://​doi.​ org/​10.​1038/​s41467-​020-​17290-6 	34.	 Y.J. Guo, P.F. Wang, Y.B. Niu, X.D. Zhang, Q.H. Li et al.,  Boron-doped sodium layered oxide for reversible oxygen  redox reaction in na-ion battery cathodes. Nat. Commun.  12(1), 11 (2021). https://​doi.​org/​10.​1038/​s41467-​021-​25610-7 	35.	 F.X. Ding, C.L. Zhao, D. Zhou, Q.S. Meng, D.D. Xiao et al.,  A novel ni-rich ­O3-na ­Ni0.60Fe0.25M0.15 O-2 cathode for na-ion  batteries. Energy Storage Mater. 30, 420–430 (2020). https://​ doi.​org/​10.​1016/j.​ensm.​2020.​05.​013 	36.	 J. Pan, S.M. Xu, T.X. Cai, L.L. Hu, X.L. Che et al., Boosting  cycling stability of polymer sodium battery by “rigid- flex- ible” coupled interfacial stress modulation. Nano Lett. 23(8),  3630–3636 (2023). https://​doi.​org/​10.​1021/​acs.​nanol​ett.​2c048​ 54
Title: High-Entropy Layered Oxide Cathode Enabling High-Rate for Solid-State Sodium-Ion Batteries ​
Authors: Tianxun Cai, Mingzhi Cai, Jinxiao Mu, Siwei Zhao, Hui Bi, Wei Zhao, Wujie Dong, Fuqiang Huang
Publisher: Nano-Micro Letters
Date: 2023-09-28 00:00:00
Abstract: Na-ion O3-type layered oxides are prospective cathodes for Na-ion batteries due to high energy density and low-cost. ​ Nevertheless, such cathodes usually suffer from phase transitions, sluggish kinetics, and air instability, making it difficult to achieve high-performance solid-state sodium-ion batteries. ​ Herein, the high-entropy design and Li doping strategy alleviate lattice stress and enhance ionic conductivity, achieving high-rate performance, air stability, and electrochemically thermal stability for Na0.95Li0.06Ni0.25Cu0.05Fe0.15Mn0.49O2. ​ This cathode delivers a high reversible capacity (141 mAh g−1 at 0.2C), excellent rate capability (111 mAh g−1 at 8C, 85 mAh g−1 even at 20C), and long-term stability (over 85% capacity retention after 1000 cycles), which is attributed to a rapid and reversible O3–P3 phase transition in regions of low voltage and suppresses phase transition. ​ Moreover, the compound remains unchanged over seven days and keeps thermal stability until 279 ℃. ​ Remarkably, the polymer solid-state sodium battery assembled by this cathode provides a capacity of 92 mAh g−1 at 5C and keeps retention of 96% after 400 cycles. ​ This strategy inspires more rational designs and could be applied to a series of O3 cathodes to improve the performance of solid-state Na-ion batteries. ​