Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (05): 1177-1182.doi: 10.3866/PKU.WHXB201203092

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Doping-Coating Surface Modification of Spinel LiMn2O4 Cathode Material with Al3+ for Lithium-Ion Batteries

XIONG Li-Long, XU You-Long, ZHANG Cheng, TAO Tao   

  1. International Center for Dielectric Research, Electronic Material Research Laboratory of Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, P. R. China
  • Received:2011-12-26 Revised:2012-02-24 Published:2012-04-26
  • Contact: XU You-Long

Abstract: A doping-coating surface modification method was used to improve the cycle performance of the lithium-ion battery cathode material spinel LiMn2O4. Al was chosen as the doping element and Al(NO3)3 as the raw material. We investigated Al3+ doping of 7.1%(atomic fraction) at the temperatures of 300, 400, 500, 600, 700, 750, and 800 °C. It was found that at increasing temperatures, the maximum specific capacity of the modified samples first increased and then decreased, with a maximum at 700 °C. The fading rate increased initially with temperature as well, and then decreased, followed by a small rise with temperature. This is because the coated layer gradually reacted with the LiMn2O4 granule at elevated temperatures and became a completely solid solution layer by 750 °C. The fading rate reached the minimum at the same time. Subsequently, the solid solution layer diffused into the LiMn2O4 granule, weakening the granule protection so that the fading rate slightly increased. Among these samples, the maximum specific capacity (133.6 mAh·g-1) was for the sample treated at 700 °C for 5 h, and the fading rate was 3.4% after 50 cycles. It is shown that doping-coating surface modification with Al3+ may enable the commercial application of spinel LiMn2O4 cathode material for lithium-ion batteries.

Key words: Lithium-ion battery, Cathode material, Spinel LiMn2O4, Doping-coating surface modification, Solid solution