Synthesis and electrochemical properties of 4LiF-NiMn2O4 composite as a cathode material for Li-ion batteries
Synthesis and electrochemical properties of 4LiF-NiMn2O4 composite as a cathode material for Li-ion batteries
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锂离子电池正极材料4LiF-NiMn2O4复合材料的合成及电化学性能
DOI：
10.1016/j.jpowsour.2017.04.003
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发表时间：
2017
影响因子：
9.2
通讯作者：
Kenkichiro Kobayashi
中科院分区：
文献类型：
--
作者：
Yasumasa Tomita;Noritaka Kimura;Yusuke Izumi;Juichi Arai;Yoshiumi Kohno;Kenkichiro Kobayashi
以LiF和NiMn 2 O 4为原料，按摩尔比为4：1，机械球磨36-192 h，制备了LiF-NiMn 2 O 4复合材料。通过XRD、充放电测试和XPS对合成的复合材料进行了研究。球磨144 h后，LiF和NiMn 2 O 4的XRD峰消失，4LiF-NiMn 2 O 4的XRD峰较宽。4LiF-NiMn 2 O 4复合材料的放电容量随球磨时间的变化而变化，球磨144 h制备的复合材料在0.1 C、2.0-4.8 V电压下的放电容量为256 mA h g− 1。在截止电压为4.8V以上的情况下，电解质的分解沿着充电过程进行，因此充放电电流效率劣化并且放电电压降低。在没有容量限制的充放电测量中，尽管由于电解质的分解而导致充放电效率低，但是获得了310 mA h g-1的高放电容量。XPS数据表明，Ni 2+离子和Mn 3+离子在充电过程中被氧化为Ni 3+和Mn 4+离子，在放电过程中被还原为Ni 2+离子和Mn 3+离子。
4LiF-NiMn2O4composites are synthesized by the mechanical milling of LiF and NiMn2O4in a molar ratio of 4: 1 for 36–192 h. The synthesized composites are investigated by XRD, charge-discharge measurements, and XPS. A broad XRD peak of 4LiF-NiMn2O4was observed and those of LiF and NiMn2O4disappear after the milling of 144 h and more. The discharge capacity of the 4LiF-NiMn2O4composites changes with the milling time, with the composite prepared by milling for 144 h exhibiting a discharge capacity of 256 mA h g−1at 0.1 C for voltages of 2.0–4.8 V. With a cut-off voltage of 4.8 V or more, decomposition of the electrolyte proceeds along with the charge process, so the charge-discharge current efficiency deteriorates and the discharge voltage decreases. In the charge-discharge measurement without the capacity limit, although the charge-discharge efficiency was low due to the decomposition of the electrolyte, the high discharge capacity of 310 mA h g−1was obtained. The XPS data suggests that the Ni2+ion and Mn3+ion are oxidized to Ni3+and Mn4+ion in charge process up to 4.8 V and are reduced to Ni2+ion and Mn3+ion during the discharge process.