Department of Physics and Department of Complexity Science and Engineering, University of Tokyo, Chiba 277-8561, Japan.
Phys Rev Lett. 2013 Aug 2;111(5):056404. doi: 10.1103/PhysRevLett.111.056404.
The fundamental electronic structure of the widely used battery material Li(x)CoO(2) still remains a mystery. Soft x-ray absorption spectroscopy of Li(x)CoO(2) reveals that holes with strong O 2p character play an essential role in the electronic conductivity of the Co(3+)/Co(4+) mixed valence CoO(2) layer. The oxygen holes are bound to the Co(4+) sites and the Li-ion vacancy, suggesting that the Li-ion flow can be stabilized by oxygen hole back flow. Such an oxygen hole state of Li(x)CoO(2) is unique among the various oxide-based battery materials and is one of the key ingredients to improving their electronic and Li-ion conductivities.
广泛应用的电池材料 Li(x)CoO(2) 的基本电子结构仍然是一个谜。Li(x)CoO(2) 的软 X 射线吸收光谱表明，具有强 O 2p 特征的空穴在 Co(3+)/Co(4+)混合价 CoO(2)层的电子传导中起着至关重要的作用。氧空穴与 Co(4+)位和 Li 离子空位结合，表明 Li 离子的流动可以通过氧空穴回流来稳定。Li(x)CoO(2) 的这种氧空穴状态在各种基于氧化物的电池材料中是独特的，是提高其电子和 Li 离子电导率的关键因素之一。
