Synthesis and structural properties of xLi2MnO3•(1-x)LiNi0.5Mn0.5O2 single crystals towards enhancing reversibility for lithium-ion battery/pouch cells

A series of xLi(2)MnO(3)center dot(1-x)LiNi0.5Mn0.5O2 (x = 0.3, 0.4, 0.5 and 0.6) single crystals is successfully synthesized via wet mechanical ball milling. Considering the components of Li2MnO3 and LiNi0.5Mn0.5O2 in xLi(2)MnO(3)center dot(1-x)LiNi0.5Mn0.5O2, the Mn 2p X-ray photoelectron spectra are successfully refined to Mn3+ and Mn(4+ )states in each component. Through GITT evaluation of the dynamic D-Li(+) the minimum D-Li(+). value is observed for the initial charging, which is attributed to the irreversible process of Li2O being removed from the layered Li2MnO3 structure. The D-Li(+) values in the 1st charge process are lower than those in the 3rd charge process. The 0.4Li(2)MnO(3)center dot 0.6LiNi(0.5)Mn(0.5)O(2) sample exhibits the best electrochemical properties compared to the other samples. At a 0.1 C current rate, it delivers 212 mAh g(-1) without capacity loss for 100 cycles. At current rates of 1 and 2 C, it delivers 158.5 and 102.1 mAh g(-1), respectively. In the full cell state (pouch cell), the 0.4Li(2)MnO(3)center dot 0.6LiNi(0.5)Mn(0.5)O(2) sample presents practical electrochemical properties that deliver 180 mAh g(-1) for 100 cycles at a 0.1 C rate. (C) 2018 Elsevier B.V. All rights reserved.