高电压正极材料镍锰酸锂的表面包覆及其电化学性能

Preparation and Electrochemical Performance of LiCoPO_4-coated Spinel LiNi_(0.5)Mn_(1.5)O_4 Cathode Materials

设计并合成了一种新型的核-壳结构材料磷酸钴锂异质层包覆镍锰酸锂.橄榄石型的磷酸钴锂纳米颗粒均匀地生长于尖晶石型镍锰酸锂表面,磷酸钴锂包覆层不仅能够有效地诱导镍锰酸锂表面产生微量Mn^(3+),同时还能够减缓Mn^(3+)的歧化反应并阻止锰的溶出.NM-CP5样品具有最佳的电化学性能,在0.5 C的放电倍率下,容量可达137 mAh·g^(-1),充放电100次后容量仍保持132 mAh·g^(-1)(容量保持率达98.5%).

This work fabricates the composite LiNi0.5Mn1.5O4 coated by olivine-type LiCoPO4.The effects of specific coating amounts of LiCoPO4 on the electrochemical properties of LiNi0.5Mn1.5O4 are discussed in detail.When the coating amount of LiCoPO4 is 5wt%,the as-synthesized composite LiNi0.5Mn1.5O4@LiCoPO4 presents the best electrochemical properties.At the current density of 0.5C rate,the first specific discharge capacity reaches 137 mAh·g-1 and the capacity retention is up to 98.5%after 100 cycles.At the high current rate of 20 C,the discharge capacity is still up to 130 mAh·g-1.The hetero structure of LiCoPO4 induces the formation of minor Mn3+on the interface of LiNi0.5Mn1.5O4,which is very important in its high performance.