摘要
Through meticulous design, a Li-lacking Cr2O5 cathode is physically mixed with Li-rich Li（1.2）Ni（0.13）Co（0.13）Mn（0.54）O2（LNCM） cathode to form composite cathodes LNCM@x Cr2O5（x = 0, 0.1, 0.2, 0.3, 0.35, 0.4, mass ratio） in order to make use of the excess lithium produced by the Li-rich component in the first charge-discharge process. The initial coulombic efficiency（ICE） of LNCM half-cell has been significantly increased from75.5%（x = 0） to 108.9%（x = 0.35）. A novel full-cell comprising LNCM@Cr2O5composite cathode and Li4Ti5O（12） anode has been developed. Such electrode accordance, i.e., LNCM@Cr2O5//Li4Ti5O（12）（＂L-cell＂）, shows a particularly high ICE of97.7%. The ＂L-cell＂ can transmit an outstanding reversible capacity up to 250 mA h g-1and has 94% capacity retention during 50 cycles. It also has superior rate capacities as high as122 and 94 mA h g-（-1）at 1.25 and 2.5 A g-（-1）current densities,which are even better in comparison of Li-rich//graphite fullcell（＂G-cell＂）. The high performance of ＂L-cell＂ benefiting from the well-designed coulombic efficiency accordance mechanism displays a great potential for fast charge-discharge applications in future high-energy lithium ion batteries.
本文将缺锂态的Cr_2O_5正极材料与Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_2(LNCM)富锂相正极材料进行物理混合,形成了复合正极材料LNCM@x Cr_2O_5(x=0,0.1,0.2,0.3,0.35,0.4),从而在第一次充放电过程中达到有效利用富锂相所产生的不可逆的锂离子.复合之后,LNCM半电池的首次库仑效率(ICE)得到显著提高,从75.5(x=0)提高到了108.9(x=0.35).LNCM@Cr_2O_5复合正极材料和Li_4Ti_5O_(12)负极材料匹配而成的新型锂离子全电池,即LNCM@Cr_2O_5//Li_4Ti_5O_(12)("L电池")表现出高达97.7的ICE.不仅如此,"L电池"还表现出了高达250 m Ah g^(-1)的可逆容量,并且在循环50次之后仍具有94%的容量保持率.此外,在1.25和2.5 Ag^(-1)电流密度下,它还具有高达122和94 m Ah g^(-1)的放电比容量,远远优于LNCM//石墨全电池("G电池")."L电池"的高性能得益于精心设计的库仑效率匹配机制,并且在未来高能量锂离子电池的快速充放电应用中表现出巨大的潜力.
基金
supported by the National Natural Science Foundation of China(51577175)
NSAF(U1630106)
