Graphene composite porous counter electrode, preparation method and application thereof

Abstract

The invention discloses a graphene composite porous counter electrode, a preparation method and application thereof. The composite porous counter electrode is a mixture of grapheme and inorganic nanometer particles coated on a conductive substrate. The preparation method concretely comprises the following steps of: mixing the grapheme prepared through chemical reduction with the inorganic nanometer particles; adding a small amount of organic binder; coating the organic binder on a substrate material, such as metal, conductive glass or conductive plastic and the like; and obtaining the graphene composite porous counter electrode through thermal treatment. The porosity of the composite counter electrode ensures that the composite counter electrode and a liquid electrolyte have larger effective contact area; and the composite counter electrode has the photoelectric conversion efficiency equivalent to a magnetron sputtering Pt electrode when being applied to a dye sensitized solar cell. The composite electrode has the advantages of low cost, favorable stability and mechanical property and the like and has important significant on the wide application of the dye sensitized solar cell.

Description

technical field [0001] The invention designs a graphene composite porous counter electrode, a preparation method and an application thereof, and belongs to the technical field of dye-sensitized solar cell energy. Background technique [0002] While society is developing at a high speed, human beings are facing unprecedented energy crisis and environmental pollution. The use of renewable energy has become the only way for human sustainable development. As a non-polluting and clean energy device, solar cells are highly valued by governments all over the world. At present, silicon-based solar cells are mainly used widely, but their prices are very expensive. Dye-sensitized solar cells have the advantages of low cost, high stability, environmental friendliness, and can be fabricated into flexible cells. They are the most promising new solar cells to replace traditional silicon-based photovoltaic cells. Dye-sensitized solar cells are mainly composed of transparent conductive f...

AI Technical Summary

Problems solved by technology

[0003] At present, the commonly used counter electrode material is mainly metal platinum, which counters the I in the electrolyte. 3 - The reduction reaction has high catalytic performance, but it also has the following outstanding disadvantages: ①The price of raw materials is very expensive; ②It needs to be prepared by high-temperature sputtering method, so it cannot meet the requirements of large-scale roll-to-roll production of flexible batteries; ③Easy with I 3 - corroded by reaction

Graphene is a two-dimensional planar structure. Graphene sheets will spontaneously exist in an electrode in a flat, stacked configuration to minimize surface energy, and this stacked structure will address the following three aspects: Negative impact on electrode performance: the stacking and agglomeration of graphene sheets will significantly reduce the effective catalytic area; the lack of pores in the stacking structure lacks effective electrolyte transport and reaction channels; the horizontal arrangement of graphene sheets leads to its lateral conductivity Good resistance, but the resistance perpendicular to the direction of the conductive substrate is relatively large, and the internal resistance of the opposite electrode is relatively large

Many of the above factors lead to low efficiency of single-phase graphene counter electrode: Shi et al. prepared graphene counter electrode by spin coating method, and the efficiency of the dye-sensitized solar cell based on it is only 2.2%, while Pt The efficiency of the / FTO substrate is 3.98% [J.Am.Chem.Soc., 130:5856-5857 (2008).]

Although people add PEDOT-PSS conductive polymer to graphene to improve its structure, the photoelectric conversion efficiency of DSSC using it as the counter electrode is only 4.5%, compared with the efficiency of 6.3% for the cell using Pt / ITO as the counter electrode. There is still a big gap [Electrochem.Commun., 10: 1555-1558 (2008)]

Images