商用LiCoO2 材料之振實密度為2.4~2.6 g cm-1，而一般製程所合成的LiFePO4/C 材料之振實密度卻只有1.0 g cm-1 左右，導致LiFePO4 電池之體積能量密度低，對於需高功率之電動工具與電動車，不利於實際的應用。陰極材料的振實密度對鋰離子電池之體積能量密度具有影響力，但LiFePO4 材料之振實密度相關研究卻很少。近年來，已有許多學者利用融鹽法合成不同的鋰離子電池陰極材料，像是LiCoO2、 Li4Mn5O12、LiMn1/3Ni1/3Co1/3O2、Li4Ti5O12 等材料皆展現出特別的表面型態與不錯的電化學性質。在本研究中，將嘗試利用融鹽作為合成LiFePO4 陰極材料之反應介質，於煆燒過程中，提供不一樣的吸放熱反應，改變起始物的反應性質。此外，比起一般的高溫固態法，熔融態反應介質有較高的離子擴散速度，藉此加快材料反應速度，並減少煆燒時間。利用不同的鐵起始物所製備之LiFePO4/C 複合材料，會有不同的材料特性與電化學性質。因此，本研究團隊將利用融鹽法，以二價與三價鐵起始物作為鐵源，製備高振實密度LiFePO4/C 複合材料，找出最佳製程條件，並探討二價與三價鐵起始物所製備得複合材料之物化性質與電化學性質。 The tap density of the LiFePO4/C composite materials is usually 1.0 g cm?3, which is much lower than the tap density of commercially used LiCoO2 (typically 2.4–2.6 g cm?3). The low tap density LiFePO4 cathode materials leads to the low volumetric energy density of the of lithium ion batteries, which is not suitable for high power applications, such as power tools or electric vehicles. Unfortunately, little attention has been fixed on improving the tap density of LiFePO4 so far. Recently, many rsearchers have studied different types of cathode materials synthesized by molten salt method, such as LiCoO2, Li4Mn5O12, LiMn1/3Ni1/3Co1/3O2, Li4Ti5O12 et al., and these materials show special morphology and good electrochemical properties. In this work, LiFePO4 cathode materials prepared by using molten salts as reaction media. The molten salts offer unique endothermic/exothermic reactions to change the reactivity of the reactants in the sintering process. In comparison with conventional solid-state reaction, the molten salt method shows accelerated reaction rate, because the salt melt exhibits higher ion diffusion rate. LiFePO4/C composite materials synthesized by different iron sources accompanied with different material characteristics and electrochemical properties. In this study, we use divalent or trivalent iron source as the starting material to synthesize high tap density LiFePO4/C composite materials by molten salt method, and find the best process. Furthermore, we will discuss the effects of different iron sources on the material characteristics and electrochemical performance of LiFePO4/C composite materials. 研究期間：9901 ~ 9912
