The performance of the rate performance is an indispensable performance indicator for advanced batteries, especially in the field of consumer electronics or electric vehicles that require fast charging. However, power density and energy density are two independent parameters. The battery has a high energy density but with a low power density, the supercapacitor can produce high power density while the energy density is greatly attenuated. The development of an energy storage material with high energy density and high power density can greatly promote the application of wearable electronics. In order to design a high power density battery material, the dynamics of the electrode material needs to be optimized according to C = αD / L2, where D is the diffusion rate of the material and L is the diffusion length, which is related to the spatial dimension of the material. According to the above relationship, improving the rate performance includes two basic principles: 1) designing a new material with a high diffusivity; 2) optimizing the dimensions of the electrode material. Compared to the two, reducing the dimensions of the material is relatively easy to achieve, and the nanoscale electrode material exhibits higher rate performance due to its unique shorter ion/electron diffusion path.

[Introduction]

          Recently, Prof. Han Zhang from Shenzhen University and Professor OG Schmidt from Chemnitz University of Technology in Germany reported a MnOx functionalized Ti3C2Tx Mxene @CNTs composite film electrode (with Ti3SiC2 as MAX phase), benefiting from the unique structure of layering. The parallel nanocircuit composed of the composite material not only optimizes the ion and electron transmission paths, but also solves the problem of high current limitation. Considering the excellent performance of Mn-based materials in zinc ion batteries, the prepared MnOx@Ti3C2Tx exhibits high capacity in water-based zinc ion batteries while exhibiting excellent rate performance. When the current density is expanded by 100 times, the capacity is increased. The retention rate is around 50%. In addition, MnOx@Ti3C2Tx and CNTs films can be used as a positive electrode material for a binderless flexible zinc ion battery with good stability.

The results were published online in the International Famous Materials Journal Advanced Functional Materials: Nanoscale Parallel Circuitry Based on Interpenetrating Conductive Assembly for Flexible and High-Power Zinc Ion Battery.

[Graphic introduction]

Figure 1 a) Schematic diagram of MnOx@Ti3C2Tx synthesis; b) Scanning electron microscopy image of multilayer Ti3C2Tx and MnOx@Ti3C2Tx; d) Element distribution of MnOx@Ti3C2Tx: Ti, Mn and C; MnOx@Ti3C2Tx e) Transmission diagram f) High resolution Transmission map.

Figure 2: Infrared spectra of MnOx@Ti3C2Tx and XPS images of Ti and Mn elements.

Figure 3 MnOx@Ti3C2Txa) Cyclic voltammetry image at 0.5 mV s-1 scan rate; b) Constant current charge and discharge image at current density; c) MnOx@Ti3C2Tx, d) MnO2, e) MnOx@ layered Ti3C2Tx Rate performance; f) Relationship between energy density and power density of MnOx@Ti3C2Tx, including comparative data.

Figure 4 MnOx@Ti3C2Tx for a zinc ion battery performance a) GITT test chart; b) CV image at different scan rates; c) b-value of the positive and negative peak currents and d) capacity contribution, e) assembled parallel Circuit diagram.

Fig. 5 MnOx@Ti3C2Txa) Optical photo of flexible zinc ion battery device under different bending angle conditions (0~180°); b) Discharge diagram of flexible battery under different bending angles; c) Discharge diagram after multiple bending; d) Comparative constant current charge and discharge diagram under severe deformation, e) Physical display of flexible battery.

[Summary of this article]

          The material of MnOx@Ti3C2Tx prepared by this institute provides a fast and accurate path for the transmission of ions and electrons through innovative device optimization design. It breaks the limitation of high current according to the principle of parallel circuit, and makes the assembled flexible zinc ion battery display. Outstanding rate performance. The flexible film MnOx@Ti3C2Tx electrode has strong mechanical stability and power output capability as the positive electrode of the flexible zinc ion battery, and its high magnification and excellent flexibility have great potential in the application of wearable electronic devices.

Literature link:
Https://doi.org/10.1002/adfm.201901336
DOI: 10.1002/adfm.201901336
Source: WeChat public number MXene FrontierFigure