Facile synthesis of nanostructured LiMnPO4 as a high-performance cathode material with long cycle life and superior rate capability

Abstract

Lithium manganese phosphate (LiMnPO₄) has been considered as an alternative to lithium iron phosphate (LiFePO₄) for next-generation Li-ion battery cathodes because of its higher working voltage. However, facile preparation methods for high-performance LiMnPO₄ are still lacking. In this work, we propose a facile route to prepare nano-LiMnPO₄ (30–50 nm) by using citric acid (CA) as a surfactant. The addition of a small amount of CA in the precursor leads to an obvious size reduction of LiMnPO₄. After carbon-coating, nano-LiMnPO₄ exhibits excellent rate capability and long cycle life at high rates because of the small size and uniform/thin carbon coating. At a high rate of up to 20C (3.4 A g⁻¹), LiMnPO₄/C can still deliver a high discharge capacity of 96.6 mA h g⁻¹. LiMnPO₄/C also exhibits long cycle life with ∼70% capacity retained after 500 cycles at 10C. The excellent electrochemical performance of LiMnPO₄/C makes it an attractive cathode in high-power and high-energy Li-ion batteries.