Wet Mechanical Route To Synthesize Morphology-Controlled NH₄MnPO₄·H₂O and Its Conversion Reaction into LiMnPO₄

Abstract

A mechanical route using a grinding apparatus such as a planetary ball mill is a simple and scalable method to produce powder materials. However, the control of the particle shapes is difficult. In this paper, we report a wet mechanical process in water to synthesize NH 4 MnPO 4 ·H 2 O (AmMnP) with various shapes (plates, flakes, rods, and nanoparticles). This process involves planetary ball milling of inexpensive raw materials (NH 4 H 2 PO 4 and MnCO 3 ) at room temperature. Morphology-controlled AmMnP particles can be obtained by only adjusting the milling conditions such as milling time, ball size, and centrifugal acceleration. Furthermore, the conversion of AmMnP into LiMnPO 4 with two different approaches (solid-state and hydrothermal reactions) has been investigated to evaluate its future applicability as a cathode for lithium-ion batteries. As a particle synthesis with a unique morphology can be attained based on a dissolution–precipitation mechanism in a solution via a suitable combination of raw materials, the study results will promote wet mechanical processes to be widely used as classic but advanced particle synthesis method.

Smart Powder Processing for Excellent Advanced Materials and Its Applications

“…The wet mechanical processing was also applied for the morphology-controlled NH 4 MnPO 4 •H 2 O (Kozawa et al, 2019a) and NH 4 CoPO 4 •H 2 O (ACP) (Kozawa et al, 2021a), respectively. For the latter case, ACP platelets were synthesized via the wet mechanical processing of NH 4 H 2 PO 4 and Co(OH) 2 in water using a planetary ball mill.…”

Fabrication of an LiMn2O4@LiMnPO4 composite cathode for improved cycling performance at high temperatures

“…This synthetic process was slightly modified from our previous method [29]. First, spherical MnCO 3 particles were prepared by the scalable precipitation method using MnSO 4 and (NH 4 ) 2 CO 3 [30] O (AmMP) particles were prepared as the precursor of LMP via the wet mechanical method using a planetary ball mill (High-G BX254E; Kurimoto, Ltd., Japan) [31]. The raw powders (NH 4 H 2 PO 4 and MnCO 3 , total 3 g) and water (20 mL) were entered into a stainless-steel vessel (170 cm 3 ) along with 2-mm diameter Y 2 O 3 -stabilized ZrO 2 balls (100 g).…”

LiMn0.8Fe0.2PO4@C cathode prepared via a novel hydrated MnHPO4 intermediate for high performance lithium-ion batteries

“…Consequently, this route not only controls the grain size of LiMnPO 4 but also significantly reduces the generation of the impurity phase during the synthetic process. 23 Kozawa et al 24 investigated the preparation of LiMnPO 4 with a controllable morphology by ion-exchange or calcination reaction using the precursor NH 4 MnPO 4 . Additionally, Zong et al 25 used a Mn (PO 3 (OH))•H 2 O precipitate with an C 2 H 5 OH initiator as a novel Mn-P precursor to successfully synthesize LiMn 0.5 Fe 0.5 PO 4 /C using a solid-state method, which significantly improved the electrochemical performance by enhancing the conductivity and facilitating Li + diffusion.…”