Boosting Li-ion storage in Li2MnO_(3) by unequal-valent Ti4+-substitution and interlayer Li vacancies building

Lithium rich layered oxide(LRLO) has been considered as one of the promising cathodes for lithium-ion batteries(LIBs). The high voltage and large capacity of LRLO depend on Li2MnO_(3)phase. To ameliorate the electrochemical performance of Li2MnO_(3), also written as Li(Li1/3Mn2/3)O_(2), we propose a strategy to substitute Mn4+and Li+in Mn/Li transition metal layer with Ti4+, which can stabilize the structure of Li2MnO_(3)by inhibiting the excessive oxidation of O_(2)-above 4.5 V. More significantly, the unequal-valent substitution brings about the emergence of interlayer Li vacancies, which can promote the Li-ion diffusion based on the enlarged interlayer and increase the capacity by activating the Mn3+/4+redox. We designed Li0.7[Li1/3Mn2/3]0.7Ti0.3O_(2)with high interlayer Li vacancies, which presents a high capacity(290 m Ah/g at 10 m A/g) and stable cycling performance(84% over 60 cycles at 50 m A/g). We predict that this strategy will be helpful to further improve the electrochemical performance of LRLOs.