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Aqueous zinc‐ion batteries are promising energy storage devices due to their low cost, good ionic conductivity, and high safety. Conductive polyaniline is a promising cathode because of its redox activity, but because the neutral electrolyte protonates only weakly, it displays limited electrochemical activity. A polyaniline cathode is developed with proton self‐doping from manganese metal–organic frameworks (Mn–MOFs) that alleviates the deprotonation and electrochemical activity concerns arising during the charge/discharge process. The MOFs carboxyl group provides protons to prevent deprotonation and allows the polyaniline to reach a high zinc storage redox activity. The proton self‐doped polyaniline cathode has a superior specific capacity (273 mAh g−1 at 0.5 A g−1), a high rate property (154 mAh g−1 at 20 A g−1), and excellent cyclability retention (87% over 4000 cycles at 15 A g−1). This research provides fresh insight into the development of innovative polymers as cathode materials for high‐performance AZIBs. [ABSTRACT FROM AUTHOR]

A hierarchical spheroidal MnO@C heterogeneous interface as a cathode material for AZIBs and synthesized through a MOF, which exhibits the excellent cycling stability. [Display omitted] Aqueous zinc-ion batteries (AZIBs) have shown great potential as energy storage devices owing to their high energy density, low cost, and low toxicity. Typically, high performance AZIBs incorporate manganese-based cathode materials. Despite their advantages, these cathodes are limited by significant capacity fading and poor rate performance due to the dissolution and disproportionation of manganese. Herein, hierarchical spheroidal MnO@C structures were synthesized from Mn-based metal–organic frameworks, which benefit from a protective carbon layer to prevent manganese dissolution. The spheroidal MnO@C structures were incorporated onto a heterogeneous interface to act as a cathode material for AZIBs, which exhibited excellent cycling stability (160 mAh g−1 after 1000 cycles at 3.0 A g−1), good rate capability (165.9 mAh g−1 at 3.0 A g−1), and appreciable specific capacity (412.4 mAh g−1 at 0.1 A g−1) for AZIBs. Moreover, the Zn2+ storage mechanism in MnO@C was comprehensively investigated using ex-situ XRD and XPS studies. These results demonstrate that hierarchical spheroidal MnO@C is a potential cathode material for high-performing AZIBs. [ABSTRACT FROM AUTHOR]

Introduction of planktivorous fish or eutrophication can alter lake food webs, especially the zooplankton communities are susceptible to changes in top–down and bottom-up controls, and eventually lead to the dominance of harmful cyanobacteria. Hence, for the recovery of large-size zooplankton abundance that graze on cyanobacteria, there is an urgency to understand the relative roles of top–down and bottom-up effects. Although much is known about these two effects in temperate lakes, little knowledge about their relative importance in subtropical highland lakes exists, where eutrophication and stocked planktivorous fish are of particular concern. Thus, we conducted research in Lake Erhai in Yunnan plateau, China, to examine the drivers affecting the dynamics of crustacean zooplankton. Redundancy analysis (RDA) was used to analyze the effects of environmental variables, phytoplankton biomass, and planktivorous fish on the biomass and body weight of zooplankton taxa in the lake, and variance decomposition analysis was applied to examine the relative roles of the bottom–up and top–down controlling factors on zooplankton biomass. The results of RDA and Pearson correction analysis showed that total nitrogen (TN) in the water column affected phytoplankton and altered the biomass of cladocerans, while water temperature directly affects the biomass of cladocerans. These findings indicate a pronounced bottom–up control link exists from nutrients to phytoplankton, and then to zooplankton. The abundance of Japanese smelt was negatively correlated both with the biomass and body weight of cladocerans. This finding suggests the pronounced top–down control link exists from fish to zooplankton. The results of variance decomposition analysis showed that TN and zooplanktivorous predation were more important in driving total zooplankton biomass, while TN, water temperature and fish predation were more essential in the variation of zooplankton biomass. Our study provides a reference for the recovery of large-size zooplankton populations in eutrophicated lakes. [ABSTRACT FROM AUTHOR]

Aqueous zinc-ion batteries is considered as a promising system for large scale electrochemical energy storage system owing to their intrinsic safety, and low cost. Nevertheless, the industrialization process is slow due to the constraints of high-performance cathode materials. Adjusting the layered structure of V 2 O 5 through metal ion or polymer intercalation can effectively improve low electron conductivity, vanadium dissolution, and slow ion transport kinetics. Herein, the conductive polymer polypyrrole-intercalated V 2 O 5 ·H 2 O (PVOH) was successfully prepared via simple hydrothermal method and following interface polymerization reaction. Getting benefit from the insertion of polypyrrole, the prepared PVOH composite material achieves a V 2 O 5 cathode with a more open structure, rich active sites, and greater stability, allowing for an expanded crystal plane spacing of 14.5 Å. Therefore, the PVOH electrode demonstrates a discharge capacity of 475 mAh g−1 and a cycling stability of 95 % capacity retention after 2000 cycles. The intercalating conductive polymers strategy can become a new approach to improve the electrochemical behavior of vanadium oxide cathodes. [Display omitted] • The conductive polymer polypyrrole-intercalated PVOH was successfully prepared. • The PVOH has a more open structure, rich active sites, and an expanded crystal plane spacing of 14.5 Å. • The PVOH electrode demonstrates a discharge capacity of 475 mAh g−1 at 0.1 A g−1. • A detailed investigation is conducted on the co-insertion mechanism of Zn2+/H+ by the different ex-situ characterization. [ABSTRACT FROM AUTHOR]

• A new strategy was raised for controlling Mn3+ of LNMO via MOFs. • An optimal LNMO electrode is demonstrated with a high discharge capacity of 145.3 mA h g−1. • The effects of MOFs on the structure and electrical properties of LNMO were investigated. Spinel LiNi 0.5 Mn 1.5 O 4 has drawn considerable attention due to its wide working voltage, high energy density, low cost, natural abundance, and environmental friendliness. However, as an electrode in lithium-ion batteries, its inferior ionic/electronic conductivity and high Mn3+ concentration at the surface lead to low specific capacitance and poor rate/cycling performance, which have impeded its applications. In this work, a series of LiNi 0.5 Mn 1.5 O 4 is synthesized via a hydrothermally assisted method coupled with a high-temperature calcination process based on metal-organic frameworks. In addition, this study systematically explores the effect of the organic ligand species on the electrochemical properties of synthesized LiNi 0.5 Mn 1.5 O 4. Furthermore, an optimal LiNi 0.5 Mn 1.5 O 4 electrode is demonstrated with a high discharge capacity of 145.3 mA h g−1 at a 1C rate. It provides a large capacity of 122.6 mA h g−1 even at a discharge rate as high as 20C. In particular, at an elevated temperature, 94.4% of the capacity is retained after 500 cycles at 1C and 40 °C. Thus, LiNi 0.5 Mn 1.5 O 4 will be a promising cathode for applications in next-generation lithium-ion batteries with high energy densities. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • PEDOT/Ni-Mn-Co-O hybrids were synthesized under different doping agent. • The action mechanism of dopants on materials is systematically explored. • Max. capacitance of PEDOT:SCS/NMCO was 540 F g−1 in KOH and increased to 98.3% after 5000 cycles. Abstract The excellent hole-conducting poly(3,4-ethylenedioxythiophene) (PEDOT) is able to improve the electrochemical properties of nickel cobalt manganese oxides (NMCOs). In this work, we applied solvothermal-coprecipitation coupled with oxidative polymerization to synthesize a hybrid of PEDOT /Ni-Mn-Co-O and investigated the influence of different doping anions on its supercapacitor performance. The anions analyzed in this work were 4-methylbenzenesulfonate, camphorsulfonate, dodecyl benzene sulfonate, sulfamate, and sulfosalicylate. The electrochemistry, physical properties, specific capacitance, and specific discharge of the hybrid samples were determined for single electrodes in 6 M KOH. With PEDOT:SCS/NMCO high doping levels per monomer were achieved, and the hybrid exhibited overwhelming electrochemical properties with a specific capacitance of 540 F g−1 at a current density of 1 A g−1, and a good capacitance retention of 98.3% after 5000 cycles at a high current density of 5 A g−1. Furthermore, the influence of the structure, molecular chain length, and the degree of conjugation of the doping anions on the doping level and electrochemical performance of the prepared materials were investigated. These results provide an important theoretical basis for the application of PEDOT based compounds in energy storage. [ABSTRACT FROM AUTHOR]

Abstract Traditional approaches to recycle and regenerate spent lithium-ion batteries by leaching are polluted and complicated. In this study, a green and simple technique has been provided to regenerate spent LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode material, besides, the regenerated mechanisms are investigated. Studies indicate that lost lithium ions in material lattice are replenished by added lithium, meanwhile, insulting impurities on particle surface remove basically, cracked and broken particles disappear during the regeneration process. Electrochemical tests demonstrate that the performances of regenerated material improve significantly. The discharge capacities are 164.6 mAh g−1 at 0.1 C rate and 147 mAh g−1 at 1 C rate, respectively. They still could deliver a discharge capacity of 131 mAh g-1 with a high capacity retention rate of 89.12% after 100 cycles at 1 C, which can be considered as a preferable electrical energy storage system. The improved electrochemical performances prove a facial and effective regeneration process. [ABSTRACT FROM AUTHOR]

The phenomenon of ordered self-assembly on solid substrates is a topic of interest in both fundamental surface science research and its applications in nanotechnology. The regulation and control of two-dimensional (2D) self-assembled supra-molecular structures on surfaces have been realized through applying external stimuli. By utilizing scanning tunneling microscopy (STM), researchers can investigate the detailed phase transition process of self-assembled monolayers (SAMs), providing insight into the interplay between intermolecular weak interactions and substrate–molecule interactions, which govern the formation of molecular self-assembly. This review will discuss the structural transition of self-assembly probed by STM in response to external stimuli and provide state-of-the-art methods such as tip-induced confinement for the alignment of SAM domains and selective chirality. Finally, we discuss the challenges and opportunities in the field of self-assembly and STM. [ABSTRACT FROM AUTHOR]

In order to control cyanobacteria blooms with silver carp in Lake Taihu, an in situ experiment was carried out by stocking silver carp at a biomass of 35, 70, and 150 g m-3 and no carp control in waterproof enclosures. Physicochemical water parameters and biomass of plankton were measured in enclosures to evaluate the suitable stocking density of silver carp for relieving internal nutrients and constraining cyanobacteria growth in Lake Taihu. It is found that the 35 g m-3 silver carp group and 70 g m-3 silver carp group presented lower total phosphorus, lower chlorophyll-a, and higher water transparency. Increased nitrogen to phosphorus ratio, which indicated the result of algae decline in fish presence enclosures, was attributed to decline of phosphorus. Phosphorus decline also exerted limitation on reestablish of cyanobacteria bloom. Crustacean zooplankton biomass and Microcystis biomass decreased significantly in fish presence enclosures. Silver carp could be more effective to regulate algae bloom in enclosures with dense cyanobacteria. Therefore, nonclassic manipulation is supposed to be appropriate method to get rid of cyanobacteria blooms in Lake Taihu by stocking 35 to 70 g m-3 silver carp in application. [ABSTRACT FROM AUTHOR]

• Using biomanipulation to restore a eutrophic highland lake in subtropical China was tested. • Fish removal led to increased abundance of cladoceran (Daphnia spp., especially Bosmina spp.). • Enhanced top-down control was found leading to lower phytoplankton and cyanobacterial biomass. • Fish removal may be a feasible additional restoration tool to nutrient loading reduction such lakes. Removal of planktivorous fish is used extensively in northern temperate lakes to reduce phytoplankton abundance via enhanced zooplankton grazing. However, whether this method would work also in large subtropical highland lakes to alleviate cyanobacterial blooms is unknown. We conducted a one-year pilot in situ experiment where we removed a substantial biomass of fish in a fenced-in area, followed by a 3-year whole-lake experiment where the dominant fish species (Japanese smelt) was removed in Lake Erhai in southwest China. The fencing experiments showed that between July and November, when the biomass of the removed stock reached 4 g/m2, the zooplankton biomass inside the fence increased significantly compared to a control fence. In the full-lake experiment, we found that sustained removal of Japanese smelt led to an increase in the biomass of cladocerans (Daphnia spp. but especially of Bosmina spp.) and a significant decrease in the biomass of Cyanobacteria and Chlorophyta. Additionally, a marked increase in the ratio of zooplankton to phytoplankton biomass, as well as an increase in the body size of cladocerans, emphasising the importance of enhanced top-down control for mitigating cyanobacterial blooms following extensive fish removal. Our results reveal that removal of small fish (here Japanese smelt) can lead to a reduction of the phytoplankton and cyanobacteria biomass through a trophic cascade in highland deep subtropical lakes. Thus fish removal may be a feasible additional restoration tool to external nutrient loading reduction in such lakes. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract A Li-rich cathode material Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 is obtained via a facile hydrothermal treatment combined with post-sintering lithiation using cetyltrimethylammonium bromide (CTAB), polyvinyl pyrrolidone (PVP), or sodium dodecyl benzene sulfonate (SDBS) as a surfactant. The prepared materials are characterized in detail using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Among all samples, Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 (C-LLNMO), with the assistance of CTAB, possesses the smallest particle size and the most uniform distribution, which is mainly due to the preferential adsorption and electrostatic repulsion of CTAB during hydrothermal treatment. Benefiting from these microstructural advantages, the C-LLNMO cathode exhibits the highest specific discharge capacity of 270 mAh g−1 at 0.1 C. Meanwhile, C-LLNMO displays excellent electrochemical stability, with a capacity retention of 89.5% at 1 C after 200 cycles, and a high rate capability reaching 149.2 mAh g−1 at a charge-discharge rate of 5 C. The fundamental cause of this enhanced electrochemical performance is the regulation of the structure and morphology of Li-rich materials using CTAB during the hydrothermal process [ABSTRACT FROM AUTHOR]

Background: Long working hours and effort-reward imbalance (ERI) among medical workers may contribute to poor mental health and reduced productivity. However, the potential mechanisms among them are not well understood. This study aimed to explore the role of depressive symptoms and ERI in the relationship between long working hours and presenteeism among village doctors. Methods: We conducted a cross-sectional study in Jiangsu Province, eastern China. 705 village doctors were assessed for working hours, ERI (the Effort-Reward Imbalance Questionnaire, ERI questionnaire), presenteeism (6-item Stanford Presenteeism Scale, SPS-6 Scale), and depressive symptoms (12-item General Health Questionnaire, GHQ-12). A moderated mediation model was used to test the role of depressive symptoms (M), and ERI (W) in the relationship between long working hours (X) and presenteeism (Y). Results: 45.11% of the village doctors worked more than 55 h per week, and 55.89% were exposed to ERI. The prevalence of depressive symptoms among Chinese village doctors was 40.85%. Long working hours (≥ 55 h per week) were significantly associated with presenteeism behaviors (β = 2.17, P < 0.001). Mediation analysis demonstrated that depressive symptoms (GHQ score > 3) could partly mediate the relationship between long working hours and presenteeism (indirect effect β = 0.64, P < 0.001). Moderated mediation further indicated that the interaction of long working hours and ERI was significantly and positively associated with depressive symptoms, which in turn predicted elevated presenteeism behaviors. Conclusions: Depressive symptoms had a mediating role in the association of long working hours with presenteeism behaviors among Chinese village doctors and ERI augment their negative effects. [ABSTRACT FROM AUTHOR]

The electrolytes based on lithium difluoro(oxalate)borate (LiODFB) and sulfolane (SL) including LiODFB-ethylene carbonate (EC)/dimethyl carbonate (DMC) and LiPF 6 -EC/DMC as the references have been studied on electrochemical performance and interfacial stability in Li/LiNi 0.5 Mn 1.5 O 4 cells. LiODFB-containing electrolytes show outstanding electrochemical stability within 5.5 V due to the passivation phenomenon on the cathodes, while LiPF 6 -containing electrolytes undergo continuous decomposition beyond 4.5 V. The initial charge/discharge profiles and cyclic voltammetry (CV) curves prove that the cell with LiODFB-SL/DMC(2:1 by vol.) electrolyte has lower degree of polarization and better reversibility. The cathode with LiODFB-SL/DMC(2:1 by vol.) electrolyte displays the best cycling performance and the cathode with LiPF 6 -EC/DMC(1:1 by vol.) electrolyte displays the worst cycling performance. AC impedance shows that the cell cycling with LiODFB-SL/DMC(2:1 by vol.) electrolyte has much smaller resistance of charge transfer on cathode/electrolyte interface than the cell cycling with LiODFB-EC/DMC(1:1 by vol.) electrolyte. The characterization of the cathode surfaces indicates that a more homogeneous and compact passivation layer forms on the cathode cycling with LiODFB-SL/DMC(2:1 by vol.) electrolyte to greatly improve the interfacial stability for the reason that SL motivates the passivation reaction of LiODFB and itself participates the formation of the passivation layers. Therefore, LiODFB-SL/DMC(2:1 by vol.) is a promising electrolyte for LiNi 0.5 Mn 1.5 O 4 cathode. [ABSTRACT FROM AUTHOR]

Spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) cathode with high voltage plateau at around 4.7 V (vs. Li/Li+) and high energy density has attracted great attention. However, its application is limited because of the lack of matched electrolyte. Herein, we demonstrate that lithium difluorophosphate (LiPO 2 F 2 , LiDFP) as lithium difluoro(oxalate)borate (LiODFB) electrolyte additive significantly improves the electrochemical performance of high voltage LNMO/Li half cells and LNMO/G full cells at room temperature. Capacity retention of LNMO/Li half cell with 4% LiDFP achieves 89.69% after 200 cycles in comparison with 76.31% of that without LiDFP. Even discharging at 10C, the LNMO/Li half cell with 4% LiDFP still delivers a discharge capacity of 76.25 mAh g−1 and maintains at 75.94% capacity retention after 200 cycles. The electrochemical performance of LNMO/G full cells has a similar improvement. The enhanced electrochemical performance of LNMO can be ascribed to the steady and low-impedance cathode electrolyte interphase (CEI) film formed by priority decomposition of LiDFP. Besides, in order to further reveal the mechanism of film-forming additive, we studied on the changes of CEI film during initial cycles using transmission electron microscopies (TEM), X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectrometer (FT-IR) and electrochemical impedance spectroscopy (EIS) measurements. The results indicate that the LiDFP preferential decomposition product can gradually prevent the contact between the electrolyte and the cathode with the growth of the CEI film, thereby reducing decomposition of the electrolyte. The finally grown CEI film is sufficiently dense to effectively isolate the electrolyte and the cathode, and CEI film formed by LiDFP-containing electrolyte is more conducive to the transmission of Li+,eventually leading to excellent electrochemical performance for the high-voltage LIBs. [ABSTRACT FROM AUTHOR]

Polyaniline/CoRE x Fe 2− x O 4 (RE=La, Ce, Y, x =0.05–0.25) nanocomposites were successfully synthesized by a novel coordination-oxidative polymerization-hydrothermal method, and doped by sulfosalicylic acid. The resultant nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and electromagnetic measurements. The composites mainly showed nanofibers with a diameter of ca. 70 nm and a length longer than 2 μm. The surface of composites was uniformly covered with numerous nanoparticles with an average size of ca . 10–20 nm. Microwave absorption properties of polyaniline/CoRE x Fe 2− x O 4 nanocomposites doped with La ion were found to be better than those doped with Ce and Y ions. For the polyaniline/CoLa x Fe 2− x O 4 nanocomposite, the optimal microwave absorption performance is at x =0.15, that is, the mass ratio of La in CoLa x Fe 2− x O 4 is 7.5%, with the conductivity of the composite about 0.833 S/cm. Furthermore, when the layer thickness is 2 mm, the maximum reflection loss achieves the maximum number of −42.65 dB at 15.91 GHz with a bandwidth of 6.14 GHz above −10 dB loss, suggesting that these nanocomposites are excellent in microwave absorbing capacity. [ABSTRACT FROM AUTHOR]

Artificial enhancement of lakes using filter-feeding silver carp is a technique that is widely used to manipulate and/or promote fisheries' production in Chinese lakes. To evaluate the impact of this enhancement on nutrient cycling in the water column, we analyzed two silver carp biomass gradient testing sites by stocking experimental enclosures within Lake Taihu (eutrophic) with 0, 35, 70 and 150 g m − 3 of silver carp biomass and those within Lake Erhai (mesotrophic) with 0, 20, 50 and 100 g m − 3 of silver carp biomass. Total phosphorus and dissolved nitrogen were obviously influenced by the fish density. At relatively low densities, the silver carp were able to graze for particles of food directly, resulting in a decline in phosphorus and chlorophyll- a levels within the Lake Taihu enclosures. When fish were introduced to the Lake Erhai enclosures, chlorophyll- a levels increased. Increased dissolved nitrogen levels were recorded in the Lake Taihu enclosures during the experiment, while the enhanced uptake of nutrients by increased algae resulted in decreased dissolved nitrogen levels in the Lake Erhai enclosures. We hypothesize that although silver carp could potentially reduce cyanobacteria in water bodies with large algal blooms, the relatively small change in fish in Lake Taihu is still too minor to control severe algal blooms. In relatively clean water bodies such as Lake Erhai, artificial ecological enhancement using silver carp should be evaluated carefully before action is taken in order to assess the risk of increasing small algal blooms and nutrients. [ABSTRACT FROM AUTHOR]

[Display omitted] • The functionalized graphene/polyaniline composite cathode showed high specific capacity and excellent rate performance. • A large conductive network was assembled by functionalized graphene and polyaniline. • The formation of -N-Zn-O- structure efficiently enhanced the Zn2+ storage behavior during discharging process. • A novel H+ and Zn2+ insertion mechanism was presented in this work. Polyaniline (PANI) as a typical conductive polymer has been widely applied in cathode materials of aqueous zinc ion battery (AZIB), owing to the features of high electronic conductivity and simple synthesized methods. However, the cycling instability caused of spontaneous deprotonation still limited the extensive application of PANI cathode materials. In this work, a functionalized commercial graphene (MEG) and PANI composite (MGP-1) was successfully assembled by a facile two-step method. When the MGP-1 acted as cathode material in AZIB, it demonstrated a high capacity of 184.5 mAh/g (0.2 A/g) and excellent rate performance of 137.6 mAh/g (3 A/g) compared to the PANI cathode. The corresponding analysis revealed that the boosted electrochemical behavior of MGP-1 was attributed to the large conductive network fabricated by the MEG and PANI, and the formations of -N-Zn-O- structures during discharging process. Moreover, based on the conventional H+ insertion mechanism, this work furtherly provided a H+ and Zn2+ insertion mechanism. In addition, the utilization of cheap and abundant commercial graphene would allow the graphene/polyaniline composite to be a promising cathode material applied in AZIB. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zn x Cd 1-x S was firstly applied to photo-Fenton system as catalyst and co-catalyst. • The ZCS-3 photo-Fenton system exhibited satisfactory catalytic performance. • The photocatalysis of that system was synergized with co-catalysis. The exploration of new catalysts or co-catalysts to promoting the circulation efficiency between Fe3+ and Fe2+ in photo-Fenton system is of great significance for sewage treatment. Herein, metallic sulfides (Zn x Cd 1-x S) with different molar ratio of Zn/Cd were constructed by a facile solvothermal technology and applied to photo-Fenton system as both catalyst and co-catalyst for the first time. The catalytic activity of photo-Fenton systems could be enhanced by adding any as-prepared samples. Moreover, photo-Fenton system containing ZCS-3 (molar ratio of Zn:Cd = 3:7) presented the highest degradation rate for Rhodamine B (RhB, 93.5%), which showed significant improvement compared with that of photo-system without ZCS-3(43.7%). The excellent performance of this photo-Fenton system was mainly ascribed to the synergistic effect between photocatalytic and co-catalytic of ZCS-3. EPR and XPS results confirmed that the Zn2+ in the ZCS-3 would be reduced to Zn+ by the •O2–, which generated under visible light irradiation in photo-Fenton system. Thereby, more Zn+/Zn2+ exposed on the ZCS-3 surface during this photo-Fenton reaction, ensuring the acceleration of conversion between Fe2+ and Fe3+. The catalytic mechanism revealed that the formation of stable double recycles of Zn2+/Zn+ and Fe2+/Fe3+ in catalytic process displayed prominent enhancement for the catalytic properties of the photo-Fenton system. [ABSTRACT FROM AUTHOR]

• A three-dimensional mesoporous microsphere structural β-MnO 2 /PPy composite was obtained using a facile hydrothermal method. • The electric PPy nanowires linked each β-MnO 2 nanorods to significantly enhance the energy storage behavior of β-MnO 2. • The total capacity was dominated by the synergistic effect between the diffusion-controlled and capacitive behavior. [Display omitted] Mn-based materials as a cathode have drawn much attention in aqueous zinc-ion batteries (AZIBs) for its advantages of low cost and environmental friendliness. However, the sluggish reaction kinetics and low structural stability still limit the electrochemical application of Mn-based materials. Herein, a β-MnO 2 / polypyrrole (PPy) composite was synthesized using a facile hydrothermal method. It delivered a remarkable specific discharge capacity of 361.8 mAh g−1 at a current density of 0.2 A g−1 and great rate performance compared to pure MnO 2 powder. And morphological and electrochemical characterizations revealed that the enhanced electrochemical performance of β-MnO 2 /PPy composite was mainly attributed to the high conductivity of PPy nanowires and the 3D mesoporous microsphere structure, which was assembled by β-MnO 2 nanorods and PPy nanowires. This article provided a new sight of synthesizing Mn-based materials/conducting polymer composites for high-performance cathode in zinc-ion batteries. [ABSTRACT FROM AUTHOR]