Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Cu-Mn”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

3 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Ab Initio Studies of Discharge Mechanism of MnO 2 in Deep-Cycled Rechargeable Zn/MnO 2 Batteries

Rechargeable alkaline Zn/MnO 2 batteries are an attractive solution for large-scale energy storage applications. Recently, Bi and Cu additives have been used to increase the cycle life and capacity of rechargeable Zn/MnO 2 batteries, with an equivalent of the full two-electron capacity realized for many cycles, in the absence of zinc. However, the mechanism of the effect of Bi and Cu on the performance of rechargeable Zn/MnO 2 batteries has not been investigated in detail. We apply first-principles density functional computational methods to study the discharge mechanisms of the unmodified and Bi/Cu-modified γ -MnO 2 electrodes in rechargeable alkaline Zn/MnO 2 batteries. Using the results of our calculations, we analyze the possible redox reaction pathways in the γ -MnO 2 electrode and identify the electrochemical processes leading to the formation of irreversible discharge reaction products, such as hausmannite and hetaerolite. Our study demonstrates the possibility of formation of intermediate Bi-Mn and Cu-Mn oxides in deep-cycled Bi/Cu-modified MnO 2 electrodes. The formation of intermediate Bi-Mn and Cu-Mn oxides could reduce the rate of accumulation of irreversible reaction products in the MnO 2 electrode and improve the rechargeability and cyclability of Zn/MnO 2 batteries.

25 ENERGY STORAGE↗
DOE OSTI2020

Materials Data on MnCu3 by Materials Project

Cu3Mn is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Mn is bonded to twelve equivalent Cu atoms to form MnCu12 cuboctahedra that share corners with six equivalent MnCu12 cuboctahedra, corners with twelve equivalent CuMn4Cu8 cuboctahedra, edges with eighteen equivalent CuMn4Cu8 cuboctahedra, faces with eight equivalent MnCu12 cuboctahedra, and faces with twelve equivalent CuMn4Cu8 cuboctahedra. All Mn–Cu bond lengths are 2.60 Å. Cu is bonded to four equivalent Mn and eight equivalent Cu atoms to form CuMn4Cu8 cuboctahedra that share corners with four equivalent MnCu12 cuboctahedra, corners with fourteen equivalent CuMn4Cu8 cuboctahedra, edges with six equivalent MnCu12 cuboctahedra, edges with twelve equivalent CuMn4Cu8 cuboctahedra, faces with four equivalent MnCu12 cuboctahedra, and faces with sixteen equivalent CuMn4Cu8 cuboctahedra. There are six shorter (2.59 Å) and two longer (2.61 Å) Cu–Cu bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn4Cu by Materials Project

CuMn4 is alpha La-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are five inequivalent Mn sites. In the first Mn site, Mn is bonded to nine Mn and three equivalent Cu atoms to form MnMn9Cu3 cuboctahedra that share corners with twelve MnMn9Cu3 cuboctahedra, edges with six equivalent CuMn6Cu6 cuboctahedra, edges with eighteen MnMn9Cu3 cuboctahedra, faces with six equivalent CuMn6Cu6 cuboctahedra, and faces with twelve MnMn9Cu3 cuboctahedra. There are three shorter (2.40 Å) and six longer (2.49 Å) Mn–Mn bond lengths. All Mn–Cu bond lengths are 2.62 Å. In the second Mn site, Mn is bonded to twelve Mn atoms to form MnMn12 cuboctahedra that share corners with three equivalent CuMn6Cu6 cuboctahedra, corners with nine MnMn9Cu3 cuboctahedra, edges with three equivalent CuMn6Cu6 cuboctahedra, edges with twenty-one MnMn9Cu3 cuboctahedra, and faces with eighteen MnMn9Cu3 cuboctahedra. There are six shorter (2.49 Å) and three longer (2.57 Å) Mn–Mn bond lengths. In the third Mn site, Mn is bonded to twelve Mn atoms to form MnMn12 cuboctahedra that share corners with three equivalent CuMn6Cu6 cuboctahedra, corners with nine MnMn9Cu3 cuboctahedra, edges with three equivalent CuMn6Cu6 cuboctahedra, edges with twenty-one MnMn9Cu3 cuboctahedra, and faces with eighteen MnMn9Cu3 cuboctahedra. There are three shorter (2.40 Å) and six longer (2.49 Å) Mn–Mn bond lengths. In the fourth Mn site, Mn is bonded to twelve Mn atoms to form MnMn12 cuboctahedra that share corners with three equivalent CuMn6Cu6 cuboctahedra, corners with nine MnMn9Cu3 cuboctahedra, edges with three equivalent CuMn6Cu6 cuboctahedra, edges with twenty-one MnMn9Cu3 cuboctahedra, and faces with eighteen MnMn9Cu3 cuboctahedra. There are a spread of Mn–Mn bond distances ranging from 2.40–2.57 Å. In the fifth Mn site, Mn is bonded to twelve Mn atoms to form MnMn12 cuboctahedra that share corners with three equivalent CuMn6Cu6 cuboctahedra, corners with nine MnMn9Cu3 cuboctahedra, edges with three equivalent CuMn6Cu6 cuboctahedra, edges with twenty-one MnMn9Cu3 cuboctahedra, and faces with eighteen MnMn9Cu3 cuboctahedra. There are a spread of Mn–Mn bond distances ranging from 2.40–2.57 Å. Cu is bonded to six equivalent Mn and six equivalent Cu atoms to form CuMn6Cu6 cuboctahedra that share corners with six MnMn12 cuboctahedra, corners with six equivalent CuMn6Cu6 cuboctahedra, edges with six equivalent CuMn6Cu6 cuboctahedra, edges with eighteen MnMn9Cu3 cuboctahedra, faces with six equivalent CuMn6Cu6 cuboctahedra, and faces with twelve equivalent MnMn9Cu3 cuboctahedra. All Cu–Cu bond lengths are 2.49 Å.

36 MATERIALS SCIENCE↗