Ultrafast Charging-Discharging of Nano-sized Na₃V₂(PO₄)₃ Embedded in Porous Carbon Matrix for Sodium Ion Batteries
Processes and Methods (incl. Screening) : Chemical
New Materials
Ref.-No.: 1201-4746-LC
Background
Sodium ion batteries are regarded as a promising alternative to lithium ion batteries due to the abundance and cheapness of sodium. Unfortunately, sodium-based cathodes exhibits poor electrochemical performance as their energy and power densities do not reach the values of lithium-based analogues. Therefore, the investigation of new sodium-based cathodes with good electrochemical performance is highly demanded.
Technology
We offer a new sodium-based composite nanomaterial for sodium ion battery cathodes. These carbon-coated nanosized Na3V2(PO4)3 particles embedded in a highly effective mixed conducting porous carbon matrix (denoted as (C@NVP)@pC) can be easily prepared by means of a facile soft-chemistry based preparation method with a post heat-treatment procedure (Fig. 1).
Fig.1: Sketch of the facile soft-chemistry-based double carbon-embedding approach for (C@NVP)@pC.
The so fabricated cathodes are highly porous and feature ultrafast performance and excellent cycling stability (Fig. 2). The charge-discharge profiles approve ultrafast charges and discharges within few seconds delivering both high energy and high power density. Moreover, it is to highlight that even after 1000 charge-discharge cycles at 100 C rate this cathode material maintains its original morphology and structure.
Fig. 2: Electrochemical characterization of (C@NVP)@pC. (C@NVP)@pC/electrolyte /Na cells are constructed and tested within the electrochemical windows of 2.9-3.9 V. 1 C means the full capacity can be charged or discharged in 1 h and 1 C = 110 mA/g in this work. (a) Galvanostatic charging−discharging profiles of (C@NVP)@pC at different current rates. (b) Long cycling stability of (C@NVP)@pC at various high current rates and Coulombic efficiency for 1000 cycles at 100 C.
Furthermore, the results show that the electrochemical performance of the novel (C@NVP)@pC cathode matches or even outshines the common high-power lithium-based cathode materials (Fig.3).
Fig.3: Comparison of high rate performance of our (C@NVP)@pC with some of best reported high-rate Li cathodes: a) capacities vs. discharge rate (C); b) capacity retention (to the low C-rate) vs. C rate; c) Rate performance of (C@NVP)@pC in comparison with homemade carbon-coated LiFePO4. The same battery assembly procedure was used, showing the potential of outperforming Li cathodes. d) Comparison of high rate performances between NVP/C and LFP/C with different carbon content.
Our results show that the soft-chemically prepared (C@NVP)@pC are very promising for application as cathodes in sodium ion batteries. They can be charged and discharges in 6 s with high current density of 22 A/g and delivers the specific capacity of 44 mAh/g and remains morphological and structure stable even after 1000 charge-discharge cycles.
Advantages
- Usage of abundant and low priced element sodium
- Facile soft-chemistry based preparation method
- High rate charge and discharge properties
- Long cycling stability
Literature
C. Zhu, K. Song, P. A. van Aken, J. Maier, Y. Yu, "Carbon-Coated Na3V2(PO4)3 Embedded in Porous Carbon Matrix: An Ultrafast Na-Storage Cathode with the Potential of Outperforming Li Cathodes", Nano Letters 2014 14 (4), pp. 2175-2180
Patent Information
PCT priority appliction WO2015067316 filed November 2013, nationalized in EP and US.
EP3066708B1 granted, nationalized in DE, FR, GB.
PDF Download
- Ref.-No.: 1201-4746-LC (1.0 MiB)
Contact person
Dr. Lars Cuypers
Senior Patent- & License Manager
Chemist
Phone: +49 89 / 29 09 19-21
Email:
cuypers@max-planck-innovation.de