Al2O3 coating on BaLi2Ti6O14 surface to boost its stability and rate performance

BaLi2Ti6O14, a promising anode material for lithium-ion battery application, was successfully prepared by a sol-gel method. To improve the structural stability and electrochemical performance of the materials, an ionic conductive Al2O3 layer was introduced. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the particles become smaller and distribute more uniformly because of the coating, and possible mechanism was discussed. Our experiments further showed that BLTO-4 sample has the best electrochemical performance. Furthermore, excessive coating will lead to a decrease of reversible capacity, because Al2O3 has no electrochemical activity. The charge and discharge capacities of BLTO-4 are 174.9 and 175.9 mAh g−1 after 50 cycles at 0.2 C, which are much higher than those of the pure sample (107.3 and 108.4 mAh g−1). Even at 10 C, BLTO-4 still delivers a reversible specific capacity of 98.6 mAh g−1 after 1000 cycles. The good cyclic stability and rate performance of BLTO-4 can be attributed to the reduced particle size and the advantages of the Al2O3 coating layer, which is favorable for the enhancement of the structural stability and the reduction of the charge transfer resistance of the materials.