SEARCH · Engineering Papers

Results for “Mn2P2O7”

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.

SourceResearch connectionFrom yearThrough year

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

3 records

All sources NASA NTRS DOE OSTI

DOE OSTI2020

Materials Data on Mn2P2O7 by Materials Project

Mn2P2O7 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Mn2+ is bonded to six O2- atoms to form distorted MnO6 octahedra that share corners with six equivalent PO4 tetrahedra and edges with three equivalent MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 2.16–2.34 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with six equivalent MnO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–60°. There is three shorter (1.54 Å) and one longer (1.60 Å) P–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Mn2+ and one P5+ atom. In the second O2- site, O2- is bonded in a linear geometry to two equivalent P5+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Mn2+ and one P5+ atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Mn2P2O7 by Materials Project

Mn2P2O7 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are two inequivalent Mn2+ sites. In the first Mn2+ site, Mn2+ is bonded to six O2- atoms to form distorted MnO6 octahedra that share corners with six equivalent PO4 tetrahedra and edges with three equivalent MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 2.16–2.38 Å. In the second Mn2+ site, Mn2+ is bonded to six O2- atoms to form distorted MnO6 octahedra that share corners with six equivalent PO4 tetrahedra and edges with three equivalent MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 2.16–2.30 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with six MnO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 44–61°. There are a spread of P–O bond distances ranging from 1.53–1.60 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Mn2+ and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Mn2+ and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two Mn2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to two equivalent P5+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

New Synthesis Strategies to Improve Co-Free LiNi0.5Mn0.5O2 Cathodes: Early Transition Metal d0 Dopants and Manganese Pyrophosphate Coating

In this work, we report solution-based doping and coating strategies to improve the electrochemical performance of the Co-free layered oxide cathode LiNi0.5Mn0.5O2 (LNMO). Small amounts of d0 dopants (e.g., Mo6+and Ti4+, 0.5-1 at. %) increase the cathode’s specific capacity, cycling stability, and rate capability. More specifically, a Mo-doped cathode with the nominal composition LiNi0.495Mn0.495Mo0.01O2 achieves a high reversible capacity of 180 mAh/g at 20 mA/g with good retention at higher rates (e.g., 120 mAh/g at 100 mA/g). Effects of 1 at.% Mo dopant on the cathode structure were studied using a suite of characterization tools including X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). These measurements demonstrate that Mo6+ reduces Li+/Ni2+cation mixing and mitigates undesirable phase transformations near the cathode surface during cycling. This work also reports the use of an inorganic Mn2P2O7 coating which enhances cycling stability, presumably through formation of a stable cathode electrolyte interphase (CEI) layer. Overall, the synthesis approaches reported herein are quite general and can potentially be expanded to other high voltage LIB cathodes.

Co-free cathodes, d0 cation, pyrophosphate coating↗