Reversible sulfate-anion involved charge storage in layered MnO₂ for aqueous symmetric batteries

Abstract

Aqueous rechargeable batteries are promising for large-scale energy storage, but MnO₂ electrodes suffer from manganese dissolution and Jahn-Teller-related instability. Here, we investigate sulfate-anion-involved charge storage in layered δ-MnO₂ symmetric cells. Ex situ spectroscopy, thermal analysis, and elemental mapping show state-dependent sulfur signals accompanied by Mn valence evolution and modest, partially reversible local coordination changes. First-principles calculations indicate that sulfate accommodation and migration within a modeled interlayer are energetically plausible. These results support sulfate-coupled charge compensation and suggest possible interlayer accommodation, while surface adsorption, near-surface storage, and electrolyte trapping cannot be excluded under the present ex situ conditions. The MnO₂ electrode delivers 154.2 mAh g^-1 at 0.2 A g^-1, and the symmetric cell achieves 107.94 Wh kg^-1 at 180 W kg^-1 with 93.7% capacity retention after 3,000 cycles. This work provides evidence for sulfate-coupled charge compensation in layered MnO₂.

Keywords

Aqueous battery / sulfate-coupled charge compensation / layered MnO₂ / symmetric cell

References

[1] Abedi P,Hosseini SA.Rational design of a superhydrophilic step-scheme MnO₂/NiCo-layered double hydroxide heterojunction anchored on anodized graphite substrate as a photoanode for boosted water splitting activity.J Environ Chem Eng2026;14:120697

[2] Dong S,Yang J.An aqueous proton battery under alkaline electrolyte.Energy Storage Mater2025;74:103888

[3] Kulkarni A,Macleod J,Kim T.Toward safe and reliable aqueous ammonium ion energy storage systems.Adv Energy Mater2024;14:2400702

[4] Agustiana D,Siburian DM,Liu H.Cathode materials for advanced lithium-ion batteries: developments, challenges, and emerging trends.Mater Res Bull2026;195:113842

[5] Plakia L.A review on design, synthesis and application of composite materials based on MnO₂ for energy storage.Energies2025;18:3455

[6] Hu Y,Gu H.Anion redox-driven engineering of layered MnO₂ cathodes for high-capacity aqueous Al-ion batteries.Chem Eng J2025;524:168881

[7] Hao Y,Ma H.Natural low corrosive phytic acid electrolytes enable green, ultrafast, stable and high-voltage aqueous proton battery.Energy Storage Mater2024;70:103455

[8] Ran Y,Sun S.Aqueous zinc-based batteries: active materials, device design, and future perspectives.Adv Energy Mater2025;16:2406139

[9] Liu Y,Yue M.Thermodynamically stable colloid dispersion electrolytes with the Tyndall effect for practical zinc-ion pouch cells.Energy Environ Sci2026;19:589-604

[10] Poudel MB,Ojha GP.Nitrogen coordinated atomically dispersed manganese catalyzes oxygen reduction in practical zinc-air batteries and alkaline fuel cells.J Power Sources2026;678:239959

[11] Poudel MB,Lohani PC,Kwak HB.Enhanced electrochemical performance of dendritic Fe₂O₃ nanowires on hollow carbon nanofibers with manganese and phosphorus co-doping for solid-state symmetric supercapacitors.J Power Sources2026;661:238447

[12] Bacirhonde PM,Kang K.Understanding the metal-center mediated adsorption and redox mechanisms in a FeMn(NbTa)₂O₆ columbite material for anion exchange membrane water electrolyzers.Adv Energy Mater2025;15:2404479

[13] Karim OLA,Bhandari T.Integrating iron phthalocyanine and cobalt nanoparticles encapsulated N-doped CNTs as bifunction electrocatalyst for oxygen evolution reaction and oxygen reduction reaction in high-efficiency zinc-air battery.J Alloys Compd2026;1071:188725

[14] Kannan R,Nahm KS.One-pot synthesis and electrocatalytic performance of Pd/MnO_x/graphene nanocomposite for electrooxidation of ethylene glycol.Int J Hydrogen Energy2015;40:11960-7

[15] Shi M,Wu ZS,Zhang X.Aqueous organic batteries using the proton as a charge carrier.Adv Mater2023;35:2302199

[16] Zhang A,Zhang X.2D layered MnO₂ with an ultralarge interlayer spacing for aqueous zinc ion batteries.ACS Appl Energy Mater2024;7:1298-305

[17] Wang J,Chen C.Orbital-guided crystal phase engineering of MnO₂ via d-orbital-free alkali metal cation pillaring for high-stability supercapacitors.J Alloys Compd2025;1047:185145

[18] Yang H,Chen D.Protocol in evaluating capacity of Zn-Mn aqueous batteries: a clue of pH.Adv Mater2023;35:2300053

[19] Yang S,Du Y,Zhao D.Hydrogen bond engineering in aqueous electrolytes: strategies for cryogenic battery applications.Energy Storage Mater2025;82:104576

[20] Wang X,Yang W.Bohr magnetons: microscopic disruptors of layered MnO₂ structures.Adv Funct Mater2025;35:2500650

[21] Wang L,Zhou W.Cation-in-mesopore complex for 20 Ah-level aqueous battery.Angew Chem Int Ed2025;137:e202501010

[22] Zhao J,Lan H.An anode-free sodium dual-ion battery.Energy Storage Mater2024;70:103480

[23] Zuo Y,Tian H.Enhanced H⁺ storage of a MnO₂ cathode via a MnO₂ nanolayer interphase transformed from manganese phosphate.ACS Nano2023;17:5600-8

[24] Wang S,Huang K.Cooperative Jahn-Teller effect and engineered long-range strain in manganese oxide/graphene superlattice for aqueous zinc-ion batteries.Nat Commun2025;16:5191 PMCID:PMC12137938

[25] Shi H,Zhang Y.Anode-less Li-based metal batteries and beyond: challenges, strategies, and prospects.Mater Today2025;83:446-83

[26] Qin R,Li S.Proton storage and transfer in aqueous batteries.Matter2025;8:102165

[27] Ruan P,Qin L.Achieving highly proton-resistant Zn-Pb anode through low hydrogen affinity and strong bonding for long-life electrolytic Zn//MnO₂ battery.Adv Mater2023;35:2300577

[28] Wang F,Zhu H.Mitigating the interfacial concentration gradient by negatively charged quantum dots toward dendrite-free Zn anodes.Energy Storage Mater2023;58:215-21

[29] Yadav P,Rai AK.A review on solutions to overcome the structural transformation of manganese dioxide-based cathodes for aqueous rechargeable zinc ion batteries.J Power Sources2023;555:232385

[30] Gao X,Su C.Recent advances in carbon-based nanomaterials for multivalent-ion hybrid capacitors: a review.Energy Environ Sci2023;16:1364-83

[31] Li G,Zhang S.Developing cathode materials for aqueous zinc ion batteries: challenges and practical prospects.Adv Funct Mater2023;34:2301291

[32] Li L,Meng J.Boosting the capacitance of MOF-derived carbon-based supercapacitors by redox-active bromide ions.Chem Eng J Adv2023;14:100484

[33] Loh JR,Lee WSV.Challenges and strategies in the development of zinc-ion batteries.Small Methods2023;7:2300101

[34] Yang Y,Wei H.Weakly solvating effect spawning reliable interfacial chemistry for aqueous Zn/Na hybrid batteries.Adv Energy Mater2023;13:2203729

[35] Zhang M,Dong Q.Organic molecular intercalated V₃O₇·H₂O with high operating voltage for long cycle life aqueous Zn-ion batteries.Adv Funct Mater2023;33:2213187

[36] Zhang R,Ni Y.Bifunctional interphase with target-distributed desolvation sites and directionally depositional ion flux for sustainable zinc anode.Angew Chem Int Ed2023;62:e202304503

[37] Chen J,Jiang J.Challenges and perspectives of hydrogen evolution-free aqueous Zn-ion batteries.Energy Storage Mater2023;59:102767

[38] Li L,Ma H.Toward the high-performance lithium primary batteries by chemically modified fluorinate carbon with δ-MnO₂.Small2023;19:2300762

[39] Liang G,Ji X.Non-metallic charge carriers for aqueous batteries.Nat Rev Mater2020;6:109-23

[40] Yao H,Zheng Y.Pre-intercalation of ammonium ions in layered δ-MnO₂ nanosheets for high-performance aqueous zinc-ion batteries.Angew Chem Int Ed2023;62:e202315257

[41] Jin Y,Liu L.Joint charge storage for high-rate aqueous zinc-manganese dioxide batteries.Adv Mater2019;31:1900567

[42] Liu L,Huang L.Alkali ions pre-intercalated layered MnO₂ nanosheet for zinc-ions storage.Adv Energy Mater2021;11:2101287

[43] Wu D,King ST.Simultaneous elucidation of solid and solution manganese environments via multiphase operando extended X-ray absorption fine structure spectroscopy in aqueous Zn/MnO₂ batteries.J Am Chem Soc2022;144:23405-20

[44] Dai L,Sun L.Jahn-teller distortion induced Mn²⁺-rich cathode enables optimal flexible aqueous high-voltage Zn-Mn batteries.Adv Sci2021;8:2004995 PMCID:PMC8224442

[45] Yu F,Zhou R,Wang H.Pseudocapacitance contribution in boron-doped graphite sheets for anion storage enables high-performance sodium-ion capacitors.Mater Horiz2018;5:529-35