3results about How to "Improve voltage efficiency" patented technology

The application discloses a vanadium ion flow battery with a praseodymium sulfide composite graphite felt electrode and belongs to the technical field of flow battery electrodes. The electrode comprises a graphite felt base body and a surface-loaded praseodymium sulfide composite layer, the composite layer is composed of praseodymium sulfide nanoparticles and carbon nanomaterials, and the particle size of the nanoparticles is 5-50 nm. Preparation is carried out by mixing a praseodymium source and a sulfur source to prepare a precursor, mixing the precursor with a carbon nanomaterial dispersion liquid, performing graphite felt thermal oxidation pretreatment, hydrothermal reaction, washing and drying, and inert atmosphere heat treatment. In the application, inorganic rare earth praseodymium sulfide is used to replace organic sulfide and nitrogen-doped carbon material, Pr 3+ / Pr 4+ is used to realize efficient catalysis, the electrode is resistant to strong acid, stable in a wide temperature range, firmly combined at an interface, and long in cycle life. The electrode can be used in all-vanadium, zinc-bromine, iron-chromium and other flow batteries, is also applicable to the fields of hydrogen production by electrolysis, supercapacitors and electrocatalysis, and is mild in process and easy to scale up.

This invention discloses a carbon-plastic bipolar plate for a zinc-bromine flow battery, its preparation method, and its application, belonging to the field of electrochemical energy storage technology. The method includes: dispersing nitrogen-doped hollow carbon nanotubes and spraying them onto the positive electrode side of a carbon-plastic bipolar plate; after drying, a nitrogen-doped hollow carbon nanotube-modified positive electrode carbon-plastic bipolar plate is obtained; dispersing boron-nitrogen co-doped carbon and spraying it onto the negative electrode side of a pretreated carbon-plastic bipolar plate, after drying again, a boron-nitrogen co-doped carbon-plastic negative electrode carbon-plastic bipolar plate is obtained. On the positive electrode side, the nitrogen-doped hollow carbon nanotubes catalyze the bromine reaction through nitrogen doping, reducing the overpotential; the hollow structure adsorbs bromine species and uses charge action to inhibit bromine permeation, reducing self-discharge. On the negative electrode side, the boron-nitrogen co-doped carbon uses B-N zinc-loving sites to guide uniform and dense zinc deposition, inhibiting dendrite formation; and inhibits hydrogen evolution through charge regulation. Both methods synergistically improve the bromine barrier performance, reaction kinetics, and dendrite suppression ability of the carbon-plastic bipolar plate.

The invention belongs to the technical field of electrochemical energy storage, and relates to a positive and negative differential integrated electrode for a static filmless zinc-bromine battery and a battery stack. The electrode comprises a flexible graphite composite bipolar plate, one side of the flexible graphite composite bipolar plate is compounded with a non-conductive negative electrode thin pre-oxidized felt subjected to oleophobic modification, the other side of the flexible graphite composite bipolar plate is compounded with a positive electrode thick activated graphite felt which has a gradient pore structure and is loaded with a bromine oxidation reduction catalyst, the contact side of the bipolar plate and the negative electrode felt is activated, and the three layers are compounded into an integrated structure. The stack is horizontally placed, positive and negative electrode felts of adjacent electrodes are directly attached and compressed, no diaphragm exists, and the compression ratio is controlled by a limiting column. Three-dimensional uniform deposition of zinc is guided through the negative electrode non-conductive felt, the bromine oil phase is locked through cooperation of positive electrode gradient pores and gravity settling, the contact resistance is reduced through the integrated structure, non-film static operation is achieved, the cycle life exceeds 500 times, the self-discharge rate is lower than 0.45%, the energy efficiency is higher than 80%, the structure is simplified, and the lithium ion battery is suitable for large-scale production.