摘要
Alkali and alkaline ion substitutions enhance the electrochemical properties of P2 sodium layered oxide,while the effect on electrochemical property enhancement of alkali and alkaline ions co-substitution is still unclear.In this work,the structural and electrochemical properties of the Li alkali and Mg alkaline ions co-substituted P2 layered oxide Na_(0.67)(Li_(0.5)Mg_(0.5))_(0.1)(Ni_(0.33)Mn_(0.67))_(0.9)O_(2)are investigated in detail.Compared to the pristine and single-ion substituted materials,the co-substituted material shows an enhanced cycling performance with a reversible ca-pacity of 127 mAh/g and a capacity retention of 75%over 100 cycles at 0.5C.Galvanostatic intermittent titration technique(GITT)and cyclic voltammetry(CV)results show that the Li and Mg synergistically improve the ion diffusion.Moreover,the structure stability is also improved by the Li and Mg co-substitution that is clarified by operando X-ray diffraction(XRD)measurements.These results explain the origin of the enhanced electrochemical properties of the Li/Mg co-substituted P2 layered oxides for sodium ion batteries.
基金
supported by Guangdong Basic and Applied Basic Research Foundation(2019A1515110897 and 2019B1515120028)
supported by Ministry of Higher Education of Malaysia for the Fundamental Research Grant(FRGS/1/2018/STG02/UM/02/10)awarded to Woo Haw Jiunn
University of Malaya research grant(GPF 038B-2018)
