posted on 2016-01-14, 00:00authored byXinyi Dai, Aijun Zhou, Jin Xu, Yanting Lu, Liping Wang, Cong Fan, Jingze Li
Surface
coating of composite electrode has recently received increasing attention
and has been demonstrated to be effective in enhancing the electrochemical
performance of lithium ion battery (LIB) materials. In this work,
an electronic-insulating but ionic-conductive lithium carbonate (Li2CO3) is rationally selected as the unique coating
material for commercial LiCoO2 (LCO) cathode. Li2CO3 is a well-known constitute in conventional solid electrolyte
interface (SEI) layer, which can electrochemically protect the electrode.
The carbonate coating layer is deposited on LCO composite electrodes
via a facial magnetron sputtering approach. The sputtered Li2CO3 layer serves as an artificial SEI layer between the
active material and electrolyte and can impede the formation of the
primary SEI layer, which will permanently consume Li+ and
reduce the reversible capacity of the electrode. After a 10 min Li2CO3 coating, the capacity retention of the composite
electrode is improved from 64.4% to 87.8% when cycled at room temperature
in the potential range of 3.0–4.5 V vs Li/Li+ for
60 cycles. The obtained discharge capacity is extended to 161 mAh
g–1, which is 36% higher than the uncoated one (118
mAh g–1). When further increasing the charging potential
up to 4.7 V, or elevating the operation temperature to 55 °C,
the Li2CO3-coated LCO electrodes still display
remarkably improved cycling stability.