Background: Olivine structured LiMnPO4 is a pioneering energy-storage material
of Li+-ion batteries. Its synthesis in a shape of small plates (large free-surfaces) bonding over
a C-sp2 surface layer is demanded in harvesting its functional properties.
Objective: In situ
synthesis of grafted LiMnPO4
of nanopaltes with a C-sp2
surface layer, with
tailored impedance properties.
Method: A simple hydrothermal reaction is explored in a solution LiOH·H2
with sodium dodecyl sulphate (a surfactant) to synthesize LiMnPO4
of small plates.
A phase pure LiMnPO4
is obtained in 8-12 h heating a precursor solution at 150°C in an
autoclave, and then washing a recovered powder in hot water.
Results: The sample LiMnPO4
contains nanoplates of a Pmnb
orthorhombic crystal structure,
/g surface area, 30-40 nm thickness, and self-assemblies. The lattice parameters a =
0.6104 nm, b = 1.0468 nm and c = 0.4758 nm describe a marked 0.43 % lattice expansion over
the bulk phase, with an enhanced aspect ratio c/a = 0.7795 above the bulk value 0.7777, which
likely promotes the charge-carrier dynamics. In the HRTEM images, the LiMnPO4
a GO-surface layer of a conductive 2D-network with sp2
-C electrons. Uniquely, a cell made of
the sample yields largely enhanced (i) conductivity of Li+
ions and electrons at a 10-6 S-cm-1
scale and (ii) Li+
diffusion coefficient 3.291x10-14
at room temperature.
Conclusion: The results describe LiMnPO4
nanoplates with an inbuilt surface C-sp2
extend fast charge diffusion kinetics useful for powerful Li+
- ion batteries.