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Flexible rechargeable zinc-ion batteries (ZIBs) have aroused tremendous attention owing to the good safety and abundant reserves, making it one of the most promising alternatives for novel energy storage devices. Herein, flexible, free-standing hybrid films with a three-dimensional interlaced network are reported for ZIBs. The flexible and pliable VO 2 /MXene hybrid films deliver a high specific capacity of 228.5 mAh g À 1 at 0.2 A g À 1 and display a reversible capacity over 126.6 mAh g À 1 after 700 cycles at 2 A g À 1. More impressively, the flexible electrode also shows exciting mechanical flexibility and outstanding Zn 2 + storage capability with a moderate capacity retention of 72.1 % after 2500 cycles at 5 A g À 1 in quasi-solidstate ZIBs. The special structure can boost the diffusion pathway of Zn 2 + and effectively stabilize the structure of the electrode upon cycling. This work also evidences that the flexible VO 2 / MXene hybrid films own an immense potential for portable and flexible equipment.

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The optimization of the production process of metal mines has been traditionally driven only by economic benefits while ignoring resource efficiency. However, it has become increasingly aware of the importance of resource efficiency since mineral resource reserves continue to decrease while the demand continues to grow. To better utilize the mineral resources for sustainable development, this paper proposes a multi-objective optimization model of the production process of metal mines considering both economic benefits and resource efficiency. Specifically, the goals of the proposed model are to maximize the profit and resource utilization rate. Then, the fast and elitist Non-Dominated Sorting Genetic Algorithm (NSGA-II) is used to optimize the multi-objective optimization model. The proposed model has been applied to the optimization of the production process of a stage in the Huogeqi Copper Mine. The optimization results provide a set of Pareto-optimal solutions that can meet varying needs of decision makers. Moreover, compared with those of the current production indicators, the profit and resource utilization rate of some points in the optimization results can increase respectively by 2.99% and 2.64%. Additionally, the effects of the decision variables (geological cut-off grade, minimum industrial grade and loss ratio) on objective functions (profit and resource utilization rate) were discussed using variance analysis. The sensitivities of the Pareto-optimal solutions to the unit copper concentrate price were studied. The results show that the Pareto-optimal solutions at higher profits (with lower resource utilization rates) are more sensitive to the unit copper concentrate prices than those obtained in regions with lower profits.

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