4 results about "Cu doping" patented technology

The invention relates to the technical field of thermoelectric materials, in particular to a Bi2SeS2-based thermoelectric material and a preparation method and application thereof, the Bi2SeS2-based thermoelectric material takes Bi2SeS2 as a matrix, and the matrix is doped with a copper element and silicon carbide as a nano composite phase. According to the invention, the electric transport performance and the heat transport performance of the material are synchronously optimized through a synergistic strategy of Cu doping and SiC nano-compounding; cu doping effectively improves the carrier concentration and conductivity, SiC nano-compounding introduces a large number of nano-interfaces, the SiC nano-compounding and the point defects generated by Cu doping jointly construct a point defect-nano-interface multi-scale phonon scattering mechanism, and the lattice thermal conductivity is remarkably reduced. Moreover, the process for preparing the Bi2SeS2-based thermoelectric material is simple, the cost is low, the thermoelectricity of the Bi2SeS3 material at 773 K is successfully improved to 0.83, and a reliable way is provided for industrial application of the Bi2SeS2-based thermoelectric material.

This invention relates to a highly stable layered oxide sodium-ion battery cathode active material and its preparation method. The chemical formula of the cathode active material is K. x Na y Cu α Ni β Mn 0.6 In the chemical formula O2, x represents the K doping amount; α represents the Cu doping amount; and β represents the Ni doping amount, where 0 ≤ x ≤ 0.35, 0.32 ≤ y ≤ 0.67, 0 ≤ α ≤ 0.4, 0 ≤ β ≤ 0.4, and x + y = 0.67, α + β = 0.4; the positive electrode active material exhibits a layered stacked morphology. This invention employs a novel bi-site substitution strategy, namely, large-radius K... + Riveted to prismatic Na + Position, Cu 2+ Occupied in transition metal sites; large radius K + Occupy Na + The presence of these sites results in larger interlayer spacing, providing more sodium ion storage sites and faster ion transport channels. Furthermore, K... + The larger interlayer spacing resulting from doping corresponds to a multilayered, oriented stacking of nanosheets in the microstructure, which is beneficial for sodium ion transport. This invention possesses high Cu content. 2+ / Cu 3+ Cu substitution with a high redox potential improves the stability of the material when exposed to air and water.

The invention discloses a preparation method of a P2 type layered sodium ion positive electrode material based on Cu doping and MgO surface coating, and the preparation method comprises the following steps: (1) weighing raw materials according to a stoichiometric formula Na < 0.67 > Ni < 0.33-x > Cu < x > Mn < 0.67 > O < 2 >, and respectively dispersing the raw materials into distilled water, (2) sequentially and uniformly dispersing the dispersed solutions into an aqueous solution of citric acid, stirring in a microwave reactor, heating at the temperature of 100-110 DEG C until the solvent is completely evaporated to form green gel, grinding the gel into powder, pre-sintering at the temperature of 500-510 DEG C, taking out, uniformly grinding again, and roasting at the temperature of 950-1000 DEG C to obtain a roasted product; and (3) adding a C4H6MgO4. 4H2O solution into the roasted product suspension, stirring at the temperature of 80-90 DEG C until the solvent is completely evaporated, and roasting the powder at the temperature of 550-600 DEG C to obtain the product Na < 0.67 > Ni < 0.33-x > Cu < x > Mn < 0.67 > O < 2 > (at) y MgO. The structural stability, the interface stability and the dynamic performance of the material under a high-voltage condition are improved through a dual modification strategy of combining partial replacement of crystal lattices by copper ions (Cu < 2 + >) and surface coating of magnesium oxide (MgO).