Shanghai Institute of Ceramics has made a series of progress in the research of new high-power energy storage electrode materials

[ Instrument network instrument research and development ] Lithium-ion batteries and supercapacitors are two types of representative energy storage devices with different energy storage principles and their own characteristics. Lithium batteries have high energy density (~250 Wh kg-1) but low power density (<1 kW kg-1), while supercapacitors have high power density (~15 kW kg-1) but low energy density (<20 Wh kg-1). Exceeding the energy storage limits of the above two types of energy storage devices and developing new electrode materials that have both high energy density and high power density energy storage devices is a challenging problem in the field of chemical energy storage.

Recently, the Advanced Materials and New Energy Application Research Team of the Shanghai Institute of Ceramics, Chinese Academy of Sciences has focused on the macro-preparation method of high-specific capacitance and low-layer mesoporous carbon electrode materials, high-capacity black titanium dioxide electrode materials for extremely fast energy storage and discharge, and ultra-high-capacity black titanium dioxide electrode materials. A series of progress has been made in nanoporous niobium oxide-based single crystals for rate-capacitive energy storage, which supports breakthroughs in the performance of high-energy and high-power energy storage devices that integrate the advantages of "capacitor + battery" energy storage.

Aiming at the problem of low energy storage specific capacity of the electric double layer on the surface of carbon materials, the research team based on the early design of the high specific capacitance nitrogen-doped few-layer carbon mesopores to achieve the high-performance nitrogen-doped carbon macro preparation and practical application As a guide, new ideas for the design and preparation of materials such as "silicon atom anchoring active nitrogen", "silicon-boron/aluminum atom coordinated regulation of active nitrogen type/content", "magnesium assisted regulation of pore structure" and other new ideas for material design and preparation were proposed, and the "sol gel A new method for the large-scale preparation of nitrogen-doped disordered mesoporous carbon with small layers of carbon based on the combination of "gel-heat treatment". The resulting nitrogen-doped carbon material has a conductivity of 150 S/cm, a specific capacitance of 690 F/g, and a 30,000 cycle capacity The retention rate is 90%.

Aiming at the problem that conventional metal oxide bulk energy storage is difficult to achieve high-power energy storage, the research team used the concept of quantum capacitance in the early stage to explain the mesoporous/nanoporous scale surface quantum polarized capacitance, combined with density functional theory to calculate the density of states distribution research , Found that active nitrogen-doped titanium dioxide has a new mechanism of electricity storage of proton coupled electron reaction. Based on the preparation method of “low temperature reduction + element doping” invented in the previous period to prepare high-conductivity black titanium oxide, it was found that 9.29 at% high-concentration doped black TiO2-x:N has a specific capacitance of up to 750 F/g, which changed the wide band gap semiconductor The traditional understanding that titanium dioxide cannot be applied to supercapacitor electrodes. Related results were published on Sci. China Mater.

Aiming at the problem of poor rate performance of lithium battery anode materials, the research team proposed a "pore + single crystal" porous single crystal structure design idea that can realize the rapid migration of "ions + electrons", combining bulk phase and surface with high energy storage and extremely fast charge and discharge Excellent characteristics. Based on the previous work, the atomic scale micro-dissolution method was invented by simulating the hydrothermal alteration in nature, combined with high temperature and low oxygen partial pressure induced oxygen defects, and successfully prepared a high specific surface area nanoporous single crystal black Nb2O5-x with a lithium storage ratio The capacity is 253 mAh/g, the capacitive capacity is as high as 87%, and it has extremely high rate performance (187 mAh/g@25C@4000 cycles, 70mAh/g@250C), and the specific capacity and rate characteristics are much better than oxide performance. The "zero strain" Li4Ti5O12 material has verified that the nanoporous single crystal structure has excellent characteristics of high energy storage and extremely fast charge and discharge of the fusion phase and surface. It has been prepared and applied to ultra-high rate energy storage devices, achieving 200C Ultra-high rate storage and discharge and high energy density of 139 Wh/kg. Related results were published on iScience.

Relevant research has been funded and supported by projects such as the National Key R&D Program and the Key Field Innovation Team of the Ministry of Science and Technology. The related achievement "Structural design and performance control of high-performance electrode materials for high-power energy storage applications" won the first prize of Shanghai Natural Science Award in 2019.