Xu Lifeng, Chen Shi, Su Yuefeng, Shen Xing, He Jizhuang, Avdeev Maxim, Kan Wang Hay, Zhang Bin, Fan Weifeng, Chen Lai, Cao Duanyun, Lu Yun, Wang Lian, Wang Meng, Bao Liying, Zhang Liang, Li Ning, Wu Feng
Beijing Key Laboratory of Environmental Science and Engineering, School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
Chongqing Innovation Center, Beijing Institute of Technology, Chongqing 401120, China.
ACS Appl Mater Interfaces. 2023 Nov 29;15(47):54559-54567. doi: 10.1021/acsami.3c13858. Epub 2023 Nov 16.
Both layered- and rocksalt-type Li-rich cathode materials are drawing great attention due to their enormous capacity, while the individual phases have their own drawbacks, such as great volume change for the layered phase and low electronic and ionic conductivities for the rocksalt phase. Previously, we have reported the layered/rocksalt intergrown cathodes with nearly zero-strain operation, while the use of precious elements hinders their industrial applications. Herein, low-cost 3d Mn ions are utilized to partially replace the expensive Ru ions, to develop novel ternary Li-rich cathode material Li[RuMnNi]O. The as-designed LiRuMnNiO is revealed to have a layered/rock salt intergrown structure by neutron diffraction and transmission electron microscopy. The as-designed cathode exhibits ultrahigh lithium-ion reversibility, with 0.86 (231.1 mAh g) out of a total Li inventory of 1.15 (309.1 mAh g). The X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectra further demonstrate that the high Li storage of the intergrown cathode is enabled by leveraging cationic and anionic redox activities in charge compensation. Surprisingly, in situ X-ray diffraction shows that the intergrown cathode undergoes extremely low-strain structural evolution during the charge-discharge process. Finally, the Mn content in the intergrown cathodes is found to be tunable, providing new insights into the design of advanced cathode materials for high-energy Li-ion batteries.
层状和岩盐型富锂正极材料因其巨大的容量而备受关注，然而各相都有其自身的缺点，例如层状相的体积变化大，岩盐相的电子和离子电导率低。此前，我们报道了具有近零应变操作的层状/岩盐共生正极，但其使用贵金属元素阻碍了它们的工业应用。在此，利用低成本的3d锰离子部分替代昂贵的钌离子，开发了新型三元富锂正极材料Li[RuMnNi]O。通过中子衍射和透射电子显微镜揭示，所设计的LiRuMnNiO具有层状/岩盐共生结构。所设计的正极表现出超高的锂离子可逆性，在总锂储量1.15（309.1 mAh g）中可逆脱出0.86（231.1 mAh g）。X射线吸收光谱和共振非弹性X射线散射光谱进一步表明，共生正极的高锂存储是通过在电荷补偿中利用阳离子和阴离子氧化还原活性实现的。令人惊讶的是，原位X射线衍射表明，共生正极在充放电过程中经历极低应变的结构演变。最后，发现共生正极中的锰含量是可调的，这为高能锂离子电池先进正极材料的设计提供了新的见解。
