Abstract

Research to produce Mn-doped NaFeO₂ was conducted from a low purity Fe-precursor aims to check the reliability for the inexpensive-mass production of the compound. The NaFeO₂ was prepared through the co-precipitation method from iron sand concentrate with Fe content of 86.72% consist of the hematite-ilmenite mixture. The reaction was conducted at 650 °C for 12 h under air argon atmosphere producing a mix of β-NaFeO₂ and α-NaFeO₂, which was then mixed with Mn₂O₃ to produce Na_1-x[Fe_1-xMn_x]O_2-δ (NFMO) at various x of 0.02; 0.05; and 0.07. The result shows that Mn doping changed the crystal structure from orthorhombic into a hexagonal, P63/mmc. FTIR spectra provides peaks attributed to Na-O, Na-Fe, Mn-O, and Fe-O. Voltammetry analysis to NFMO-0.02 and NFMO-0.05 provide peaks attributed to Na⁺/Na and Fe³⁺/Fe⁴⁺ redox reaction. Meanwhile, the NFMO-0.07 provides Na⁺/Na, Fe³⁺/Fe⁴⁺, and Mn³⁺/Mn²⁺. The NFMO-0.07 also shows the highest electrical conductivity of 1.372 x 10⁻⁴ Scm⁻¹. A split cell test developed with NFMO-0.07 as cathode produced an initial specific capacity of 50.57 mAhg⁻¹ and an initial discharge capacity of 36.29 mAhg⁻¹ correlate to 71.70% Columbic efficiency.

摘要

由低纯度的铁前驱体进行了制备Mn掺杂的NaFeO _2的研究，目的是检验廉价廉价生产该化合物的可靠性。通过共沉淀法从铁砂精矿中制备出NaFeO ₂，铁含量为86.72％，由赤铁矿-钛铁矿混合物组成。将反应物在650℃下空气中进行12小时氩气氛产生的混合β-NaFeO ₂和α-NaFeO ₂，然后将其用锰混合₂ ö ₃产生的Na _1-x的[Fe _1-x的Mn _x ] O2 _-δ（NFMO）在0.02的各种x上；0.05；和0.07。结果表明，Mn掺杂使晶体结构从正交晶变为六方晶，P63 / mmc。FTIR光谱提供了归因于Na-O，Na-Fe，Mn-O和Fe-O的峰。对NFMO-0.02和NFMO-0.05的伏安分析提供了归因于Na ⁺ / Na和Fe ³⁺ / Fe ⁴⁺氧化还原反应的峰。同时，NFMO-0.07提供Na ⁺ / Na，Fe ³⁺ / Fe ⁴⁺和Mn ³⁺ / Mn ²⁺。NFMO-0.07还显示出1.372 x 10 ^-4 Scm ^-1的最高电导率。用NFMO-0.07作为阴极开发的分体式电池测试产生的初始比容量为50.57 mAhg ^-1，初始放电容量为36.29 mAhg ^-1，对应于71.70％的哥伦比亚效率。