With the surging development of flexible wearable and stretchable electronic devices, flexible energy-storage devices with excellent electrochemical properties are in great demand. Herein, a flexible Zn-ion battery comprised by hydrated zinc vanadium oxide/carbon cloth (ZnVOH/CC) as the cathode is developed, and it shows a high energy density, superior lifespan, and good safety. ZnVOH/CC is obtained by the in situ transformation of hydrated vanadium oxide/carbon cloth (VOH/CC) by an electrochemical method, and the intercalation pseudocapacitive reaction mechanism is discovered for ZnVOH/CC. The co-insertion/deinsertion of H+/Zn2+ is observed; the H+ insertion dominates in the initial discharge stage and the high-rate electrochemical process, while Zn2+ insertion dominates the following discharge stage and the low-rate electrochemical procedure. An ultrastable reversible capacity of 135 mAh g–1 at 20 A g–1 is obtained after 5000 cycles without capacity fading. Moreover, the as-assembled flexible zinc-ion battery can operate normally under rolled, folded, and punched conditions with superior safety. It is capable to deliver a high discharge capacity of 184 mAh g–1 at 10 A g–1 after 170 cycles. This work paves a new way for designing low-cost, safe, and quick-charging energy-storage devices for flexible electronics.

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The issue of degraded reversibility of zinc-metal anodes resulting from dendrite formation and surface-originated side reactions is still a fundamental challenge for high-performance zinc-ion batteries (ZIBs). Herein, a graphene oxide (GO) nanosheet-modified cellulose acetate (CA) separator is developed with an ultralow mass loading of 4 μg cm −2 by a simple and lowcost filtration method. The low lattice mismatch of GO with Zn metal and numerous hydrophilic O-containing groups of GO enable the uniform Zn nucleation and the following epitaxial electrodeposition along the (002) plane, leading to a dendrite-free surface. Significantly, the surface chemistry of GO is important as the hydrophilic O-containing groups act as the initial nuclei deposition sites, which would grow larger along the parallel direction in the subsequent process. This CA/GO composite separator elevates the symmetric cell lifespan to 500 h at a high current density of 10 mA cm −2 (1 mA h cm −2 ). Moreover, a smaller nucleation overpotential (89 mV at 1 mA cm −2 ) and excellent Coulombic efficiency (higher than 96%) can also be realized. Furthermore, such a separator engineering enables an improved cycling performance for hydrated VO 2 /CC||Zn batteries. This separator modification method provides a pathway for the development of high-performance ZIBs and expands their application in other metal-related energy devices suffering from irreversibility.

The application of transition-metal oxides in the energy storage field is hampered by its low electronic conductivity, sluggish Li + diffusion, and huge volume changes. The construction of oxygen vacancy defects can effectively modify the electronic structure of the active materials, accelerating the charge transfer process. Herein, the CoMoO 4 nanorods with different oxygen vacancy concentrations are synthesized through the facile calcination process under N 2 and Air atmospheres. The ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) analysis and Density Functional Theory (DFT) calculation results confirm that the bandgap reduces along with the increment of the oxygen vacancy content. The CoMoO 4-N 2 with higher oxygen vacancy concentration exhibits more superior electrochemical performance than CoMoO 4-Air, which delivers an ultrahigh specific capacity (999 mA h g À 1 after 500 cycles at 0.5 A g À 1), remarkable rate capacity (477 mA h g À 1 at 9 A g À 1), and excellent cycling stability (650 mA h g À 1 after 1000 cycles at 2 A g À 1).

The binary transition metal oxides have attracted great attention because of their considerable energy and power densities. However, they suffer from low reaction kinetics and large volume change, limiting their practical energy applications. The construction of a mesoporous structure with a large surface area, the development of a carbon matrix, as well as heteroatom doping can effectively overcome the above challenges. Herein, the synthesis of phosphorous‐containing Fe2VO4/nitrogen‐doped carbon mesoporous nanowires (P‐Fe2VO4/NCMNWs) is reported. In this unique structure, the atomic‐level P‐doping could increase the conductivity of Fe2VO4 by reducing its band gap, which is confirmed by DFT calculations. Furthermore, the phosphorus can covalently “bridge” the carbon layer and Fe2VO4 through P−C and Fe−O−P bondings. As a result, this anode material exhibits a high capacity (1002 mA h g−1 at 0.5 A g−1 after 250 cycles), excellent rate performance (448 mA h g−1 at 10 A g−1), and prominent long‐term cycling stability (533 mA h g−1 at 5 A g−1 after 500 cycles, 364 mA h g−1 at 10 A g−1 after 1000 cycles). All of these attractive features make the P‐Fe2VO4/NCMNWs a promising electrode material for high‐performance lithium‐ion batteries.

The development of energy management strategy (EMS), which considers how power is distributed between the battery and ultracapacitor, can reduce the electric vehicle’s power consumption and slow down battery degradation. Therefore, the purpose of this paper is to develop an EMS for hybrid energy storage electric vehicles based on Pontryagin’s minimums principle (PMP) considering battery degradation. To verify the EMS, the hybrid energy storage electric vehicle model is first established. In the meantime, the battery cycle life trials are finished in order to develop a battery degradation model. Following that, a rule-based control approach and the PMP optimization algorithm are used to allocate power in a hybrid energy storage system (HESS) in a reasonable manner. Finally, a simulation experiment under urban dynamometer driving schedule (UDDS) settings verifies the established EMS, and the findings reveal that the suggested EMS has a lower energy consumption rate and battery deterioration rate than the rule-based method.

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Echelon use batteries from electric vehicles will bring not only the cost reduction of energy storage but also the social benefits of circular using of resource, energy conservation and emission reduction. It is an important echelon use orientation that retired batteries from electric vehicles are rebuilt into distributed energy storage systems. The article introduces 8 cases of distributed energy storage systems containing echelon use batteries, whose application scenarios include load shifting, renewable energy storage, frequency modulation of power system, and capacity charge management. In summary, the reconstruction of echelon use batteries is based on battery packs or modules in order to reduce the cost of their secondary development as much as possible because the advantage of echelon use batteries is low cost after all. Echelon use batteries should be used under the regime of low rate and / or shallow charge-discharge for the sake of their cycle life and safety. Besides, a set of distributed energy storage system containing retired batteries from ROEWE e50 electric vehicles was developed by us and its application effects in a distributed PV generation station was introduced. Ten 3P3S retired batteries modules with similar capacities are rebuilt a 5 kWh energy storage system with 50 V rated voltage, whose energy transition efficiency is about 88%. Energy storage applications of retired batteries from electric vehicles in distributed PV generation not only supply electrical loads with stable power, but also achieve peak shaving of solar electric power.