[en] Highlights: • The activation of PS by Fe–EC was proposed for the first time. • The ICE–PS coupled system enhanced the corrosion of Fe. • DFT calculations identified the activation mechanism of PS by Fe–EC. • The radical process was proven in the ICE–PS coupled system. • The average %RSE was maintained at 23.1%. The greenhouse gas carbon dioxide (CO₂) was converted to a novel CO₂ conversion material (electrolytic carbon, EC) by molten salt electrochemical conversion, which served as the carbon source to prepare an iron–carbon composite (Fe–EC). The composite was used to activate persulfate (PS) and degrade 2,4-dichlorophenol (2,4-DCP) in an aqueous solution. The effects of several essential operating parameters such as PS dosage and pH on 2,4-DCP degradation were investigated. The removal efficiency of 2,4-DCP (20 mg L^–1) was 97.8% in the presence of Fe–EC (50 mg L^–1) and PS (1 mmol L^–1). Moreover, the average % reaction stoichiometric efficiency (RSE) (calculated for all selected times 5–60 min) was maintained at 23.07%. Electron paramagnetic resonance (EPR), classical radical scavenging experiments, and density functional theory (DFT) calculations were integrated for a mechanistic study, which disclosed that the active species in the system were identified as SO₄^⦁–, • OH, and ${\mathrm{O}}_2^{\mathrm{⦁}-}$. Moreover, the iron–carbon micro-electrolysis/PS (ICE-PS) system had a high tolerance to a wide range of pH, which would provide theoretical guidance for the treatment of organic pollutants in practical industrial wastewater.

[en] The utilization of Zn anodes to build aqueous Zn–metal batteries has captured extensive attention in the domain of energy storage, but this task faces scientific challenges, such as Zn dendrites and unsatisfactory stripping/plating efficiency as well as gas evolution. Herein, cation-deficient Cu${}_{2-<!--\; ???\; -->x}$Te (Cu${}_{1.81}$Te) is proposed as an attractive intercalated anode material for aqueous Zn-ion batteries. It delivers an ultraflat discharge plateau of 0.2 V (vs Zn${}^{2+}$/Zn) and a capacity of 158 mAh g${}^{-<!--\; ???\; -->1}$, of which 86% capacity is contributed from the discharge plateau at 0.2 V. Moreover, it shows superior cyclability with 100% capacity retention over 2000 cycles at 2.5 C (1 C = 242 mA g${}^{-<!--\; ???\; -->1}$). Experimental characterization reveals that it undergoes sequential insertion and conversion mechanism: Zn${}^{2+}$ is first inserted into the Cu${}_{2-<!--\; ???\; -->x}$Te which is further converted into Cu and ZnTe. Theoretical calculations demonstrate that the crystal defects in Cu${}_{2-<!--\; ???\; -->x}$Te can manipulate the electronic structure to enhance reactivity and simultaneously reduce diffusion barriers. Moreover, an aqueous "rocking-chair" Cu${}_{2-<!--\; ???\; -->x}$Te//Na${}_3$V${}_2$(PO${}_4$)${}_3$ Zn-ion full battery is demonstrated. It delivers an energy density of 58 Wh kg${}^{-<!--\; ???\; -->1}$ with a voltage output of 0.98 V, and keeps 92% capacity retention after 1000 cycles. This research provides an ultralow discharge plateau and stable anode material for aqueous Zn-ion batteries. (© 2021 Wiley-VCH GmbH)

[en] Zn metal is a promising anode material for high-energy-density aqueous batteries, but it is plagued by dendrite, low stripping/plating efficiency, and inevitable depletion of active Zn. Herein, a low-intercalation-potential material, Cu${}_7$Te${}_4$, is reported as both an anode material and Zn dendrite inhibitor for aqueous Zn batteries. A low plateau of 0.2 V (vs Zn${}^{2+}$/Zn), high capacity of 216 mA h g${}^{-<!--\; ???\; -->1}$, and superior cyclability over 4200 cycles can be realized by Cu${}_7$Te${}_4$ anode. Moreover, when Zn is modified with Cu${}_7$Te${}_4$ layer, a hybrid anode based on "intercalation-deposition" mechanism can be ingeniously developed, in which Zn${}^{2+}$ ions are sequentially inserted into Cu${}_7$Te${}_4$ and uniformly deposed on Zn at successive low potential. A battery built on such a mechanism sustains more than 1000 h and 1000 times in comparison to less than 100 h and 350 times of a bare Zn. Furthermore, an aqueous "rocking-chair" Cu${}_7$Te${}_4$//ZnI${}_2$Zn-ion full battery is further demonstrated, which can realize energy densities of 65.3 Wh kg${}^{-<!--\; ???\; -->1}$ and 86% capacity retentions after 10 000 cycles. This research contributes to a stable anode material for aqueous Zn batteries and provides an effective strategy to address the Zn dendrite. (© 2022 Wiley‐VCH GmbH)