All Binder-Free Electrodes for High-Performance Wearable Aqueous Rechargeable Sodium-Ion Batteries

Extensive efforts have recently been devoted to the construction of aqueous rechargeable sodium-ion batteries(ARSIBs)for large-scale energy-storage applications due to their desired properties of abundant sodium resources and inherently safer aqueous electrolytes.However,it is still a significant challenge to develop highly flexible ARSIBs ascribing to the lack of flexible electrode materials.In this work,nanocube-like KNiFe(CN)6(KNHCF)and rugby balllike NaTi2(PO4)3(NTP)are grown on carbon nanotube fibers via simple and mild methods as the flexible binder-free cathode(KNHCF@CNTF)and anode(NTP@CNTF),respectively.Taking advantage of their high conductivity,fast charge transport paths,and large accessible surface area,the as-fabricated binder-free electrodes display admirable electrochemical performance.Inspired by the remarkable flexibility of the binder-free electrodes and the synergy of KNHCF@CNTF and NTP@CNTF,a high-performance quasi-solid-state fiber-shaped ARSIB(FARSIB)is successfully assembled for the first time.Significantly,the as-assembled FARSIB possesses a high capacity of 34.21 mAh cm?3 and impressive energy density of 39.32 mWh cm?3.More encouragingly,our FARSIB delivers superior mechanical flexibility with only 5.7%of initial capacity loss after bending at 90°for over 3000 cycles.Thus,this work opens up an avenue to design ultraflexible ARSIBs based on all binder-free electrodes for powering wearable and portable electronics.

Boosting Zn-ion storage capability of self-standing Zn-doped Co_(3)O_(4)nanowire array as advanced cathodes for high-performance wearable aqueous rechargeable Co//Zn batteries

Neutral aqueous rechargeable Co_(3)O_(4)//Zn batteries with high-output voltage and outstanding cycling stability have yielded new insights into wearable energy-storage devices.To meet the increasing demand for a means of powering wearable and portable devices,the development of a high-performance fiber-shaped Co//Zn battery would be highly desirable.However,the intrinsically poor conductivity of C 03O4 significantly restricts the application of these high-capacity and high-rate aqueous rechargeable battery.Encouragingly,density functional theory(DFT)calculations demonstrate that the substitution of Zn for Co^(3+)leads to an insulatormetal transition in the Zn-doped Co_(3)O_(4)(Zn-Co_(3)O_(4)).In this study,we used metallic Zn-Co_(3)O_(4)nanowire arrays(NWAs)as a novel binder-free cathode to successfully fabricate an all-solid-state fiber-shaped aqueous rechargeable(AFAR)Co//Zn battery.The resulting fiber-shaped Co//Zn battery takes advantage of the enhanced conductivity,increased capacity,and improved rate capability of Zn-Co_(3)O_(4)NWAs to yield a remarkable capacity of 1.25 mAh·cm^(-2)at a current density of 0.5 mA·cm^(-2),extraordinary rate capability(60.8%capacity retention at a high current density of 20 mA·cm^(-2))and an admirable energy density of 772.6 mWh·cm^(-3).Thus,the successful construction of Zn-Co_(3)O_(4)NWAs provides valuable insights into the design of high-capacity and high-rate cathode materials for aqueous rechargeable high-voltage batteries.

超结构α-Fe2O3纳米棒作为新型无黏结剂阳极用于高性能纤维状镍/铁电池

本文首先通过溶剂热法在导电碳纳米管纤维上合成超结构α-Fe2O3纳米棒,随后在其表面包覆了一层PPy,从而获得负极材料,并用于组装了高性能全固态纤维状镍铁电池.该工作的突出亮点在于超结构3D α-Fe2O3纳米棒具有丰富的空位和通道,有效地缩短了离子传输的距离;此外,丰富的通道使离子易于与内部活性物质反应,从而改善了电化学性能,因此合成的α-Fe2O3电极材料具有高的比容量和优异的倍率性能.总的来说,本文在导电CNTF上合成具有高电化学性能的超结构α-Fe2O3@PPy核壳纳米棒电极材料.独特的超结构α-Fe2O3@PPy纳米棒由于其较大的比表面积和较高的电导率而显著改善了电化学性能;高导电性的PPy壳层亦明显增强了电子和离子的扩散.该工作有助于高能量密度水系可穿戴式电池的发展,为未来便携式和可穿戴电子产品提供动力.