Lithium-ion batteries have been widely applied in hybrid electric vehicle, laptop, mobile phone, and others due to their long cycle life and high energy density. LiCoO2 is still the most widely used cathode material in commercial lithium-ion batteries, because of its easy synthesis, high electronic conductivity, excellent cycling performance, and reasonable rate capability. However, the disadvantages, such as the high cost, limited capacity, and toxicity, limit its further development and application. With the increasing market demand, it is necessary to search for new cathode materials of the lower cost, lower toxicity, and also, ease in preparation to replace LiCoO2.
A team of researchers led by Prof. KANG Xueya at Xinjiang Technical Institute of Physics & Chemistry, CAS, recently developed a solution method to coat LiNi1/3 Co1/3 Mn1/3 O2 with LBO glass layer, and obtained the good cycling stability, high rate, and high temperature performances. The morphology, structure, and electrochemical properties of the bare and coated LiNi1/3 Co1/3 Mn1/3 O2 are characterized by scanning electron microscopy, X-ray diffraction, electrochemical impedance spectroscopy, and charge–discharge tests. The results showed that the lattice structure of LiNi 1/3Co1/3Mn1/3 O2 is not changed after coating. The coating sample shows good high-rate discharge performance (148 mAh g-1 at 5.0 C rate) and cycling stability even at high temperature (with the capacities retention about 99% and 87% at room and elevated temperature after 50 cycles). The Li+ diffusion coefficient is also largely improved, while the charge transfer resistance, side reactions within cell, and the erosion of Hydrofluoric Acid all reduced. The obtained excellent electrochemical performances of the LBO coated LiNi1/3 Co1/3 Mn1/3 O2 should enable the wide acceptance and application in long-life lithium ion batteries with high power and high energy density.
The results have been published on Journal of Solid State Electrochemistry, 2012，16:1481-1486.