Improved Electrochemical Performance of Li1.2Mn0.54Ni0.13Co0.13O2 By Surface Modification with Li-Ion-Conductive Li2TiO3

Wednesday, 31 May 2017
Grand Ballroom (Hilton New Orleans Riverside)
F. Ding, J. Li, G. Xu, and Z. Li (University of Science and Technology Beijing)
With the development of electric vehicles, hybrid electric vehicles, and electric power tools, lithium-rich oxide electrodes with layered structures have attracted considerable interest, due to their high specific capacity of about 250 mA·h/g between 2.0 V and 4.8 V. However, it suffers from intrinsic poor rate capability, voltage decay and cycle stability.

In this paper, Li2TiO3 coated Li1.2Mn0.54Ni0.13Co0.13O2 cathode materials were fabricated via a combined method of wet chemical processes and high temperature solid state method. The precursor Mn0.54Ni0.13Co0.13(OH)1.6, obtained by a co-precipitation method as reported by Y.Chen[1], and an appropriate amount of concentrated ammonia were dispersed in absolute ethanol. Afterword a mixed solution of Ti(OC4H9)4 and absolute ethanol (10 mL) was added drop-wise for 10 min. Finally, the obtained TiO2@Mn0.53Ni0.13Co0.13(OH)1.6 were thoroughly mixed with an appropriate amount of LiOH·H2O, and then calcined at 900 ℃ for 12 h in air. The Li1.2Mn0.54Ni0.13Co0.13O2 samples coated with 3 wt% and 5 wt% Li2TiO3 were denoted as LNCM-T3 and LNCM-T5 respectively. The SEM image and EDS area mapping analysis of LNCM-T3 composite material presented in Fig.1 were performed to further identify the distribution of the LTO coating layer on the surface of coated LNCM. It is seen from Fig. 1 b–f that the Ti, O, Ni, Co and Mn elements uniformly distribute in the selected region of the nanoparticles, indicating that LTO were uniformly coated on the LNCM surface. Fig.1 g shows the improved electrochemical performance of the coated samples, especially, the LNCM-T3 electrode delivers a discharge capacity of 164 mA·h/g even at a high rate of 5C, whereas only 136 mA·h/g specific capacities can be obtained for the LNCM electrode at the same rate. In addition, when the current rate is reversed back to 0.1 C, a 96% of the initial capacity (252 mA·h/g at 0.1C) was recovered for the LNCM-T3 electrode compared to 91% of the LNCM electrode, which means that 3% LTO coating sample has a better structure stability. According, LTO serve as a surface protecting layer, not only protect the active materials from the erosion of HF, which produced during the high potential charging process and long-term cycling, but also improves the velocity of Li+ migration on electrode surface, particularly, when LTO was doped with aliovalent ions[2].

Fig.1 SEM plot (a) and the corresponding EDS area mapping of Ti(b), O (c), Ni (d), Co (e) and Mn (f) for LNCM-T3. And(g)Rate capability of pristine and coated LNCM under variable current rate.


This work is financially supported by the National Natural Science Foundation of China (no.5157020571).


 [1] Chen Y, Xu G, Li J, et al. High capacity 0.5Li2MnO3·0.5LiNi0.33Co0.33Mn0.33O2 cathode material via a fast co-precipitation method[J]. Electrochimica Acta, 2013,87:686-692.

[2] Lu J, Peng Q, Wang W, et al. Nanoscale Coating of LiMO2 (M = Ni, Co, Mn) Nanobelts with Li+-Conductive Li2TiO3: Toward Better Rate Capabilities for Li-Ion Batteries[J]. Journal of the American Chemical Society, 2013,135(5):1649-1652.