A dendrite-free Zn anode enabled by PEDOT:PSS/MoS₂ electrokinetic channels for aqueous Zn-ion batteries†

Hai Wang ^a, Qin Zhao ^b, Weimin Li *^b, Shun Watanabe *^a and Xiaobo Wang *^b
aDepartment of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan. E-mail: swatanabe@edu.k.u-tokyo.ac.jp
^bState Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China. E-mail: wangxb@licp.cas.cn; liwm@licp.cas.cn

First published on 13th March 2024

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Introduction

The widespread development and adoption of renewable energy sources (e.g. solar and wind) is crucial to promoting sustainable economic growth, improving access to energy and mitigating climate change.^1–4 Aqueous zinc-ion batteries (AZIBs) based on metallic zinc anodes are promising candidates, as they offer attractive advantages including low potential (−0.762 V vs. SHE), high theoretical capacitance (820 mA h g⁻¹ or 5854 mA h cm⁻³), natural abundance, and environmental friendliness, giving them great potential for large-scale energy storage systems.^5,6 However, zinc metal anodes are always plagued by parasitic side reactions, dendrite growth and continuous corrosion. The standard electrode potential of Zn/Zn²⁺ (−0.762 V vs. SHE) is lower than that of H₂/H⁺ (0 V vs. SHE), so the HER occurs and changes the concentration of the electrolyte during the reduction of zinc, thus accelerating further corrosion of the zinc anode. The surface of the zinc anode becomes more irregular after sustained corrosion, making the nucleation site of Zn²⁺ uneven and intensifying the hydrogen evolution reaction (HER) on such a rough corroded zinc surface.^7,8

Corrosion of zinc anodes will lead to poor reversibility, low coulombic efficiency (CE), reduced capacity, and serious safety hazards. Therefore, in order to suppress dendrites and side reactions, crucial efforts should be made to achieve a uniform nucleation site for Zn²⁺ and create a uniform current distribution on the surface of the Zn anode to improve efficiency and safety by promoting the rapid transport of Zn²⁺ and inhibiting the evolution of H₂.⁹

To date, many approaches, including precise Zn electrodeposition,¹⁰ surface modification,¹¹ structural design of Zn anodes,¹² and electrolyte optimization,¹³ have been proposed to address the problem of dendrite formation and side reactions. The construction of a protective layer or buffer coating is recognized as an effective strategy to stabilize Zn metal anodes as well as to adjust the electrode/electrolyte interface chemistry It prevents side reactions arising from direct contact between fresh Zn and the electrolyte and induces a uniform charge distribution, contributing to controlled nucleation sites for Zn²⁺, thus greatly inhibiting corrosion reactions and dendrite growth in the cycle.^14,15 Examples include the natural construction of gradient ZnF₂ layers on Zn surfaces to achieve uniform Zn²⁺ stripping/plating and improve zinc reversibility,¹⁶ fabrication of three-dimensional (3D) nanoporous ZnO structures (Zn@ZnO-3D) on Zn to accelerate the kinetics of Zn²⁺ transfer and deposition, formation of artificial solid-electrolyte interfaces of nano-MOFs (ZIF-8) to improve zinc plating/stripping behaviour reversibility,¹⁷ and introduction of some conductive nanoshells¹⁸ to alleviate Zn corrosion and help mitigate dendritic growth and side reactions. In this respect, polymer coatings have an advantage over inorganic coatings, which have zincophilic properties that facilitate homogeneous nucleation and deposition of zinc. For example, polyvinyl chloride (PVB) polymers are used as artificial SEI films covering zinc anodes, and the cycling stability of the surface-modified zinc anodes can be greatly improved.¹⁹ Polyamide²⁰ (PA) and polydopamine²¹ (PDA) buffer layers can be used to isolate the active zinc from the electrolyte. However, the types of polymer coatings studied are limited and the preparation process is complicated, and the specific effective mechanisms of the corresponding zincophilic sites and polymers are not yet fully understood. It is therefore of great importance to develop polymeric protective layers through a simple preparation process, while achieving preferential orientation of zinc electrodeposits along specific crystal planes, inhibiting the growth of dendrites and weakening H₂ evolution.

Here, we propose an easily prepared polymer-based composite (PEDOT:PSS/MoS₂, PEPM) as a multifunctional protective layer to modify the surface of Zn anodes. Benefiting from the high electrical conductivity of PEDOT and the unique two-dimensional layered structure of MoS₂, PEPM can improve the mobility of Zn ions by strongly binding to Zn²⁺, spontaneously homogenize the Zn²⁺ flux and avoid tip effects. On the one hand, PEPM exhibits beneficial zincophilic properties by forming ionic bonds with Zn²⁺, which can induce uniform electrodeposition behavior, reducing the nucleation barrier of metallic Zn. Not only that, the PEPM coating also blocks direct contact between the Zn anode and the electrolyte, inhibiting the formation of the HER and by-products. The symmetric cell based on the PEPM@Zn anode exhibits a cycling stability of over 2100 h with a voltage hysteresis of ∼80 mV at 1 mA cm⁻², which is nearly 11 times longer than that of the bare Zn anode. This PEPM@Zn anode also exhibits a high average CE of 99.01% at 1 mA cm⁻² and 1 mA h cm⁻². The coulombic efficiency of the specific capacity of the assembled PEPM@Zn∥V₂O₅ full cell remains at 61 mA h g⁻¹ (99.1%) after 1000 cycles at 1.0 A g⁻¹, confirming the potential of the PEPM@Zn anode for practical applications. This method offers an attractive strategy for designing cost effective and stable zinc anodes.

Results and discussion

The molecular structure of PEDOT:PSS is illustrated in Fig. 1(a) and a schematic diagram of the preparation of the PEPM polymeric interlayer is shown in Fig. 1(b) and (c). PEDOT:PSS is synthesized by polymerizing EDOT into PEDOT, while PSS balances the electrode properties and facilitates the dissolution of PEDOT. MoS₂ is then added to the diluted solution of PEDOT:PSS to form a homogeneous suspension. With the help of electrostatic interactions and the presence of hydrogen bonds between the functional groups in the monolayer MoS₂ and PEDOT:PSS, PEPM materials can be obtained using MoS₂ as a template and PEDOT:PSS uniformly distributed on the surface. The PEPM is used as a multifunctional intermediate layer and then spray-coated on the surface of the Zn anode.

The morphology of MoS₂ and the prepared PEPM was first characterized by SEM and TEM. Fig. 1d depicts the SEM image of monolayer MoS₂ where the layered structure can be clearly observed. Fig. 1e and f and Fig. S1†show the SEM images of the PEPM, where the outer surface of MoS₂ is covered with PEDOT:PSS. The TEM images in Fig. 1g show the ultra-thin structure of the MoS₂ nanosheet, while the HRTEM images in Fig. 1h and i show distinct lattice stripes with a lattice spacing of 0.619 nm, corresponding to the (002) crystal plane of the MoS₂ crystal, indicating the successful attachment of the PEDOT:PSS composite to the monolayer MoS₂ surface.

The crystal structure and phase composition of the PEPM@Zn anode were examined by XRD. As shown in Fig. 2a, the characteristic peak of 2H-MoS₂ (PDF: #87-2416) is clearly observed in addition to the characteristic peak of metallic zinc from the substrate, indicating the successful introduction of MoS₂ nanosheets without other impurities. In addition, a weak characteristic peak from PEDOT:PSS is observed at 2θ = 17.6°, which is caused by the weak intensity of the diffraction peak of organic matter. The elemental composition and chemical state of the prepared PEPM were determined by XPS and the overall spectra are shown in Fig. 2b. As shown in Fig. 2c, the high-resolution XPS spectrum of Mo 3d has three pairs of doublet peaks at 230.4, 231.35 eV (crystalline MoS₂) and 234.1 eV (oxidation states of Mo atoms), which confirms the presence of MoS₂.^21,22 The peak at 227.15 eV is assigned to the S 2s of MoS₂.²³Fig. 2d shows the high resolution XPS spectrum of sample S 2p. A pair of peaks located at 161.51 and 162.74 eV are assigned to the basal S²⁻ and terminal carbon ligands in crystalline MoS₂, while the binding energy can be attributed to the Sr atoms in the PSS for S 2p at 167.67 and 166.41 eV.^24,25 According to the deconvoluted O 1s XPS spectrum in Fig. 2e, the fitting peak can be assigned to the CO bond (531.25 eV), the C–O bond (530.35 eV) and O²⁻ (529.5 eV). The high resolution spectrum of C 1s (Fig. 2f) has a strong peak at 282.8 eV, which corresponds to the C–C/CC species, and two relatively weak peaks at 283.4 eV and 284.25 eV correspond to C–S and C–O.²⁶ The results prove that the monolayer MoS₂ was successfully loaded into the pre-designed PEDOT:PSS composites.

The interfacial compatibility of the prepared PEPM@Zn electrodes was further tested by the contact angle (CA) with the 2 M ZnSO₄ electrolyte, as shown in Fig. 2g. It is noteworthy that the wettability of the PEPM@Zn electrode was significantly enhanced (64.7°) compared to the bare Zn electrode, which rapidly decreased to 31.2° after 10 min. In contrast, the CA of the bare Zn electrode slowly decreased from 93.2° to 71.6° during the same period. This indicates a stronger interaction between the constructed PEPM interlayer and the electrolyte that benefited from the intimate interfacial contact. The construction of the PEPM framework on the Zn anode improves the hydrophilicity of the electrode and promotes the diffusion of Zn ions at the electrode/electrolyte interface.²⁷ The elemental composition of the PEPM material was further analyzed by EDS quantitative mapping. The results in Fig. 2h show that the material consists of the elements Mo, S, C and O, with the mass and atomic proportions of each element shown in the inset.

In order to evaluate the effect of the PEPM interlayer on Zn stripping/plating, galvanostatic charge–discharge tests on symmetric cells were carried out and the results are shown in Fig. 3a and Fig. S2.† At a current density of 1 mA cm⁻² and a capacity of 1 mA h cm⁻², the symmetrical cell with the PEPM interlayer can operate stably over an extremely long lifetime of 500 h with a voltage hysteresis well below 35 mV. In sharp contrast, the symmetrical Zn cell without the PEPM interlayer exhibited poor cycling stability of only 113 h at the same current density, while the abrupt short circuit was apparently attributed to interfacial side reactions (e.g. the HER and passivation) during Zn dendritic growth. As shown in Fig. 3b, even at the higher current densities of 5 mA cm⁻² and 5 mA h cm⁻², the PEPM@Zn anode achieves a longer cycle life (up to 380 h) and a lower polarization (32 mV). This suggests that the introduction of PEDOT:PSS on monolayer MoS₂ nanosheets plays an important role in regulating dendritic-free Zn deposition, possibly due to its inherent conductivity and abundant zincophilic groups leading to a uniform and rapid Zn²⁺ flux. The corrosion resistance of PEPM coatings was evaluated using the Tafel plot with Pt and Ag/AgCl electrodes as counter and reference electrodes, respectively. Fig. S3† shows the comparison of Tafel plots and the fitted corrosion current and corrosion potential of bare Zn and PEPM@Zn anodes, and the corresponding corrosion current density decreases after introducing PEPM. Rate performance was also tested to explore the improved effect of the PEPM interlayer on zinc ion transport. As shown in Fig. 3c and Fig. S4,† the hysteresis voltage of the bare zinc half-cell varied significantly with increasing current. In contrast, the PEPM-modified zinc anode maintained stable operation at different current densities and with a low voltage hysteresis. Even under the harsh condition of 20 mA cm⁻², the PEPM@Zn anode maintained a relatively stable voltage, indicating its potential for rapid high-capacity cycling.²⁸ Higher Zn migration rates were obtained for the PEPM@Zn anode, indicating a significant improvement in the reversibility of the electrode, which corresponds to a higher CE and less irreversible capacity loss. Cyclic voltammetry curves of the symmetric cells of bare Zn and PEPM@Zn are compared in Fig. S5.† With increasing current densities of 0.5, 1, 2, 4, 6, 10 and 20 mA cm⁻², the voltage stability of the PEPM@Zn symmetric cell was 31.3, 36.8, 46.4, 63.2, 81.1, 112.0, and 177.9 mV, respectively. The Nyquist plots of the symmetric cells based on PEPM@Zn and bare Zn anodes are compared in Fig. S6† and Fig. S7.† The significantly improved cycling stability of PEPM@Zn is mainly attributed to a combined effect. (a) The PEPM overlay has abundant oxygen-containing functional groups and strong affinity with Zn atoms, which restricts the 2D diffusion of Zn²⁺ ions and inhibits dendrite formation by inducing parallel growth of Zn deposits. (b) The PEPM interlayer with certain electron conductivity will result in a uniform distribution of the surface electric field and ensure uniform deposition of Zn²⁺ ions on the Zn anode surface, thus inhibiting the formation of Zn dendrites.

To confirm the superiority of the PEPM interlayer, nucleation overpotentials were investigated by assembling Zn∥Ti or PEPM@Zn∥Ti asymmetric cells (Fig. 3d). It is evident that the nucleation overpotential of Zn@PEPM (24 mV) is much lower than that of bare Zn (58 mV) at a current density of 1 mA cm⁻² and a plating capacity of 1 mA h cm⁻², indicating that the strong interaction between the PEPM interlayer with abundant oxygen-containing groups and the Zn anode is conducive to uniform Zn growth with low nucleation barriers.^29,30 To assess the effect of the PEPM layer on the reversibility of zinc, the coulombic efficiency (CE) of the Zn∥Ti and PEPM@Zn∥Ti asymmetric cells was tested, which is determined by the ratio of the amount of zinc stripped to the amount of zinc plated in each cycle. As shown in Fig. 3e, the PEPM@Zn∥Ti cell showed an extremely stable CE over 1200 cycles, with an average CE of 99.7%. In contrast, the Zn∥Ti cell performed relatively poor and the failure occurred at 80^th cycles with an average CE of 96.0%, after which the CE fluctuated sharply, indicating non-uniform Zn stripping/plating on the Ti foil.³¹ Furthermore, the voltage profile for different cycles of PEPM@Zn consistently maintained a smaller voltage hysteresis than bare Zn, as shown in Fig. 3f, which can be attributed to the fact that the PEPM interlayer promotes uniform Zn plating/stripping while simultaneously suppressing side reactions.³² The significantly improved reversibility of PEPM@Zn is strong evidence that the PEPM overlay not only homogenizes the flow of Zn²⁺ ions near the electrode for uniform Zn plating/stripping, but also acts as a physical barrier to avoid direct contact between the anode and the electrolyte, thereby eliminating interfacial side reactions.

Impressively, the ultra-high cycle life and capacity of this work outperformed many previously reported results for interfacial modifications of ZIBs,^{33,34,35,36,37,38,39,40,41,42,43,44,45} ESI.† The results show that PEPM intercalation with functional groups effectively inhibits side reactions and dendrite growth, improving anode reversibility and achieving uniform Zn deposition during repeated stripping/plating.

The performance of the PEPM@Zn anode was further investigated in full cells by coupling it with a commercial V₂O₅ cathode to demonstrate its practical application. As shown in Fig. 4a, the CV curve shows a similar shape with two redox peaks for both cells, indicating the reversibility of the electrochemical process, corresponding to the co-insertion/extraction of Zn²⁺/H⁺.^46,47 A comparison of the CV curves of PEPM@Zn//V₂O₅ and Zn//V₂O₅ full cells is shown in Fig. S8.† Zn//V₂O₅ batteries show a smaller polarization (about 22 mV) than those with Zn anodes, which corresponds to their charge–discharge curves. Notably, narrower voltage gaps between redox peaks and higher response currents were clearly observed in the PEPM@Zn//V₂O₅ cell compared to the Zn//V₂O₅ full cell, indicating the reversibility and faster kinetics of Zn²⁺ at the V₂O₅ cathode. Fig. 4b and c show the rate performance and galvanostatic charge–discharge (GCD) performance of bare Zn//V₂O₅ and PEPM@Zn//V₂O₅ full cells at varying current densities from 0.2 to 5 A g⁻¹. At current densities of 0.2 A g⁻¹, 0.5 A g⁻¹, 1.0 A g⁻¹, 2.0 A g⁻¹, 3.0 A g⁻¹ and 5.0 A g⁻¹, the capacities of PEPM@Zn//V₂O₅ full batteries reach 225.59, 169.93, 127.37, 109.65, 102.93, and 93.47 mA h g⁻¹, respectively, providing higher rate capabilities compared to bare Zn anodes. In particular, when the current density returned to 0.2 A g⁻¹, PEPM@Zn//V₂O₅ still retained a capacity of 222.46 mA h g⁻¹ and excellent cycling stability. It is worth noting that PEPM@Zn//V₂O₅ showed a higher discharge capacity than those without PEPM under the test current. The cycling stability of the bare Zn//V₂O₅ battery was not satisfactory due to the accumulation of dead Zn and the aggravation of the aggravated parasitic reaction. The excellent rate performance of the PEPM@Zn anode can be attributed to homogenized Zn nucleation and the low polarization of the PEPM interlayer. Owing to the improved anode performance, PEDOT:PSS/MoS₂@Zn anodes can significantly reduce the activation time and achieve a higher reversible full cell capacity than a pure Zn anode, which is mainly derived from the increased electron transport rate and the appropriate ion transport rate.⁴⁸ Furthermore, the interfacial charge transfer impedance of the studied full cell was evaluated by EIS measurements. The semicircle in Fig. 4d in high frequency represents R_ct, while the larger the radius of the semicircle, the higher the resistance. It is clear that the PEPM@Zn//V₂O₅ cell exhibits a lower R_ct compared to Zn//V₂O₅, which is a consequence of the enhanced charge transfer kinetics.

The long-term stability of PEPM@Zn//V₂O₅ and Zn//V₂O₅ batteries was also investigated. With the help of the PEPM interlayer, PEPM@Zn//V₂O₅ cells show higher capacity than Zn//V₂O₅ cells while exhibiting more attractive multiplier and stable cycling performance. At a current density of 1.0 A g⁻¹ (Fig. 5e), the capacity of the PEPM@Zn//V₂O₅ cell stabilized at about 113.4 mA h g⁻¹ with no significant capacity degradation after 1000 cycles (retention: 89%). A schematic diagram of the assembled PEPM@Zn//V₂O₅ cell is illustrated in Fig. 4f. Furthermore, PEPM@Zn//V₂O₅ cells show an ultra-long cycling stability of 3000 cycles at a current density of 5.0 A g⁻¹ in Fig. 4g, with the capacity and stability significantly enhanced compared to those of Zn//V₂O₅ cells. The long-term stability and performance of Zn anodes before and after modification under different working conditions (Fig. S9†) prove the applicability of the PEDOT:PSS/MoS₂ intermediate layer. The slow rise in capacity during the initial stage can be attributed to the slow activation process, in which more active substances are slowly exposed to participate in the reaction.⁴⁹ It should be noted that the inferior rate performance of the modified anode may be related to the mismatch between the rate performance and capacity due to the larger thickness of the electrode.^50,51 The results demonstrate the unique advantage of the PEPM protective layer in alleviating parasitic side effects at the interface and suppressing capacity degradation.

To reveal the mechanism of inhibition of dendrite formation by PEPM, the Zn²⁺ deposition behavior at the anode–electrolyte interface was investigated using in situ optical microscopy. Specifically, the morphological evolution of the anode surface was observed after different plating times at a current density of 5 mA cm⁻². As shown in Fig. 5a, small Zn metal dendrites can be found on the bare Zn anode at a plating time of only 8 min, indicating an inhomogeneous Zn²⁺ flux. As the reaction time increased to 32 min, the imbalance between Zn plating/stripping intensified and was accompanied by bubble generation (shown by red arrows). In contrast, a flat and dendrite-free surface was obtained after 32 min of uniform plating by the PEPM@Zn anode due to the uniform zinc flux and the ability to inhibit dendrite growth (Fig. 5b). The structural and interfacial changes at each electrode after 500 cycles were further examined by SEM, EDS and XRD. As shown in Fig. 5c and d, no significant dendrites were detected on the surface of the PEPM@Zn anode, which is due to the uniform deposition of zinc ions induced by the nanochannel formed by the unique lamellar structure of monolayer MoS₂. As can be seen from the XRD spectra in Fig. 5e, no significant impurity peaks were detected apart from variations in intensity, which demonstrates the cycling stability of the PEPM@Zn modified anode. Combined with the ex situ EDS results in Fig. S10† and XPS results in Fig. S11,† the element content of Mo and S of the PEPM@Zn anode decreases and the Zn elemental content increases significantly compared to the pristine cell, which can be explained by the exfoliation of MoS₂ and the deposition of Zn on the anode surface.

The regulatory mechanism of the PEPM interlayer of inducing uniform Zn deposition is shown in Fig. 5f–h. Without protection, the dendrites on the anode surface grow vigorously due to the tip effect (Fig. 5f). The inhibition of Zn dendrites by PEPM@Zn derives from the synergistic effect of MoS₂ and the conducting polymer PEDOT:PSS. Monolayer MoS₂ inhibits the growth of dendrites and other side reactions such as hydrogen precipitation due to its adjustable channel size and the effective regulation of Zn deposition.^52–54 More importantly, the conductive polymer (PEDOT:PSS) on the PEPM suppresses polarization problems by enhancing the electric field on the Zn anode. Thus, the application of a PEPM interlayer on the Zn anode is effective in inducing a uniform Zn flux and inhibiting dendrite formation.^55,56

To study the effect of PEDOT:PSS on the bandgap of MoS₂, the PEDOT:PSS/MoS₂ structure was simulated by integrating the optimized MoS₂ structure with PEDOT:PSS. The interface models are established and illustrated in Fig. S12.† The calculation results in Fig. 6a and b revealed that PEDOT:PSS/MoS₂ is a semiconducting system, and the introduction of PEDOT:PSS has an enhancement effect on the band gap of MoS₂, of which the bandgap (1.43 eV) is larger than that of MoS₂ (1.37 eV). A charge density difference was obtained to investigate the indispensable role of PEDOT:PSS in the PEDOT:PSS/MoS₂ (PEPM) heterojunction and to view the redistribution of charges after the interaction, which is shown in Fig. 6c and Fig. S13.† The yellow region represents electron aggregation while the blue region indicates electron loss, of which the isosurface value is 0.0005 e per bohr³. The adsorption energy is the interaction energy between the substance and the surface, the higher the adsorption energy, the easier the adsorbent is to be adsorbed onto the surface and vice versa.

The calculation result of adsorption energy in Fig. 6d is −0.38 eV for the PEDOT/MoS₂ heterojunction and −0.19 eV for MoS₂, in which the high absolute value of the adsorption energy indicates a higher adsorption energy. Both structures have a good adsorption effect on zinc ions, and the adsorption effect of the PEDOT:PSS/MoS₂ heterojunction is slightly stronger than that of MoS₂. Bader charge results in Fig. 6e show that the Zn atom transferred 0.162 e to the PEDOT/MoS₂ heterojunction and 0.124 e to MoS₂, respectively, and the system containing PEDOT showed more interlayer charge transfer than the pure system. This indicates that the addition of PEDOT enhances the charge transfer of Zn²⁺.⁵⁷ Combined with the average charge density difference curve in the Z-direction (Fig. 6f and g), the charge transfer between Zn and PEDOT/MoS₂ is more than that between Zn and MoS₂. We also calculated the adsorption of Zn on the PEDOT/MoS₂ surface and the MoS₂ surface. The charge transfer process was further elucidated by comparing and calculating the density of states (DOS) and the partial density of states (PDOS) for MoS₂ and PEPM. As can be seen from Fig. 6h, the introduction of the conducting polymer PEDOT:PSS resulted in a significant change in the electronic structure of the original MoS₂.^58,59 The PDOS results in Fig. 6i show that incorporating PEDOT:PSS increases the available electronic states near the Fermi energy level inside the crystal, thus accelerating the Zn²⁺ diffusion kinetics and electron migration.

Conclusion

A facile construction strategy of PEDOT:PSS/MoS₂ as an interlayer (PEPM) was proposed to successfully achieve flexible, stable and dendrite-free Zn anodes. The fabricated PEPM modified interlayer regulates the uniform distribution of Zn²⁺ at the molecular scale, increases the nucleation sites on the Zn anode by regulating the ion transport pathway and provides a physical barrier that retards the formation of Zn dendrites, thus inducing uniform deposition of Zn²⁺ ions and enhancing cycling stability. The uniformly distributed electric field also ensures a more uniform and rapid entry of Zn²⁺ ions into the electrode and homogeneous Zn deposition, which offers even current distributions on both electrode/electrolyte interfaces. The PEPM@Zn anodes exhibit high coulombic efficiency, long cycling stability and dendrite-free behavior compared to their bare zinc counterparts, as well as improved electrochemical performance in both symmetric and full cells. This work provides a fundamental insight into the realization of Zn metal anode stabilization through interfacial reactions and sheds light on the roadmap of applications in rechargeable Zn batteries.

Conflicts of interest

There are no conflicts to declare.

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Footnote

† Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d4nr00465e

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