Method for rapidly prolonging circulation life of delta-MnO2 pseudo-capacitor electrode

Abstract

The invention discloses a method for rapidly prolonging the circulation life of a delta-MnO2 pseudo-capacitor electrode. According to the method, Na-contained delta-phase MnO2 is grown on a high-conductivity substrate in an electrochemical method and serves as an electrode, Zn(H2O3)n2+ is input to an interlayer tunnel of delta-MnO2 by immersion and pinned to the interlayer by a high absorption affinity of Zn(H2O3)n2+ itself, and an electrochemical performance of MnO2 is influenced. According to the method, operation is simple, the cost is low, effects are obvious, the tunnel surface structureof the delta-MnO2 based electrode material can be improved, crystal lattice distortion caused by interlayer expansion/contraction and John-teller effect in the charging/discharging process can be inhibited, the circulation life of the electrode material is prolonged, the specific capacity of the electrode material is improved, and the utilization efficiency of the material is increased. The methodis suitable for structure modification and performance improvements of the pseudo-capacitor electrode with ion preadsorption of high absorption affinity or made of MnO2 and other compounds with the tunnel structure.

Description

technical field [0001] The invention belongs to the field of electrochemical supercapacitors, in particular to a method for rapidly increasing high Na content δ-MnO 2 (Na 0.55 mn 2 o 4 ) method of pseudocapacitor electrode cycle life. Background technique [0002] Among many pseudocapacitor electrode materials, manganese dioxide (MnO 2 )-based electrode can realize rapid and large-scale energy storage in neutral aqueous solution. This material has the advantages of high theoretical capacity, low cost, environmental friendliness, and high electrochemical potential. It is one of the most promising electrode materials for large-scale development and application. . Its advantages of cost and environmental protection are far superior to ruthenium dioxide (RuO 2 ) base electrode material, and its wide electrochemical window (1V) is unmatched by many transition metal compounds. However, in actual working environment MnO 2 However, the base pseudocapacitor faces two major pr...

AI Technical Summary

Problems solved by technology

However, in actual working environment MnO 2 However, the base pseudocapacitor faces two major problems: the cycle life is lower than that of the carbon-based electric double layer supercapacitor (usually >100,000 cycles); the actual specific capacity of the thin film electrode, especially the powder electrode (<300F / g) Usually well below its theoretical capacity (~1,000F / g)

α-phase MnO 2 A class of MnO represented by 2 The main reason for the low cycle life of electrode materials is the reduction of active substances caused by the disproportionation reaction of the mesophase MnOOH during the energy storage process; the delta phase MnO 2 Because its larger tunnel structure (layered) is not suitable for proton storage, its cycle life is better than that of α-MnO 2 , but its inherent John-teller effect and repeated changes in layer spacing will also cause structural deformation and lead to capacity attenuation

while MnO 2 The main reason for the low actual specific capacity of the base electrode is its low conductivity, as well as the slow diffusion and migration speed of electrolyte hydrated cations with large mass and radius in the interface and active materials.

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