Reversible Structural Changes and High-Rate Capability of Li3PO4-Modified Li2RuO3 for Lithium-Rich Layered Rocksalt Oxide Cathodes
Reversible Structural Changes and High-Rate Capability of Li3PO4-Modified Li2RuO3 for Lithium-Rich Layered Rocksalt Oxide Cathodes
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DOI：
10.1021/acs.jpcc.8b04723
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发表时间：
2018-06
期刊：
影响因子：
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通讯作者：
Sou Taminato;M. Hirayama;Kota Suzuki;Kyungsu Kim;K. Tamura;R. Kanno
中科院分区：
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作者：
Sou Taminato;M. Hirayama;Kota Suzuki;Kyungsu Kim;K. Tamura;R. Kanno
富锂层状岩盐氧化物是一种很有前途的锂离子电池正极材料，具有超过250 mA h g-1的高充放电容量。然而，其差的速率能力仍有待解决。在这里，我们研究的非晶Li 3 PO 4的表面修饰的结构和电化学反应的表面区域的外延Li 2 RuO 3（010）薄膜电极由脉冲激光沉积制备的影响。使用表面X射线衍射（XRD），硬X射线光电子能谱，和中子反射仪的结构表征表明，表面改性由3 nm厚的Li 3 PO 4导致在部分取代的P为Li的表面区域的Li 2 RuO 3。与未改性的表面（0.3C下的5%）相比，改性的（010）表面在20 C下表现出更好的倍率性能（0.3C下放电容量的41%）。原位表面X射线衍射证实了改性表面在脱锂过程中发生了高度可逆的结构变化。
Lithium-rich layered rocksalt oxides are promising cathode materials for lithium-ion batteries, owing to their high charge–discharge capacities of over 250 mA h g–1. However, their poor rate capability remains to be addressed. Here, we investigate the effects of surface modification by amorphous Li3PO4 on the structures and electrochemical reactions in the surface region of an epitaxial Li2RuO3(010) film electrode fabricated by pulsed laser deposition. Structural characterization using surface X-ray diffraction (XRD), hard X-ray photoemission spectroscopy, and neutron reflectometry shows that surface modification by 3 nm thick Li3PO4 resulted in the partial substitution of P for Li in the surface region of Li2RuO3. The modified (010) surface exhibits better rate capability at 20 C (41% of the discharge capacity at 0.3 C) compared to the unmodified surface (5% of that at 0.3 C). In situ surface XRD confirmed that highly reversible structural changes occurred at the modified surface during lithium (de)inter...