A stable surface construction of Ni-rich LiNi0.8Mn0.1Co0.1O2 cathode material for high performance lithium-ion batteries

Nickel-rich layered materials LiNi0.8Co0.1Mn0.1O2 (NCM) is a promising candidate cathode material for next generation lithium-ion battery due to its high energy density and relatively low cost. Unfortunately, NCM suffer from capacity fading upon cycling and poor rate capability that seriously limit its wide application. To overcome these drawbacks, we present an effective inorganic coating strategy for complex LixNi1-yFeyO2&NiFe2O4 (LNFO&NFO) in-situ surface modified NCM cathode material by a sample wet-chemical method, which could effectively stably layer structure and eliminate lithium impurity. As a result, LNFO&NFO surface modified NCM shows excellent electrchemical performance. For example, the optimized NFO-2 cathode not only shows an excellent rate performance with discharge capacity of 140.56 mAh g-1 at 10 C, but also exhibits outstanding cycling stability with an improved capacity retention of 87.43% and 74.32% at 1 C after 250 and 100 cycles under room and elevated temperature of 25 and 55 oC. The superior electrochemical performance is attributed to the dual functions of NiFe2O4 modification. The formed LNFO&NFO coating layer bonds with the surface oxygen vacancy of bulk material could effectively stably surface structure and bulk structure associated with capacity degradation as well as the electrical and ionic conductivity at the interface. Therefore, an ingenious designs of the LNFO&NFO surface coating layer is a key approach for improving the durability of NCM cathode material during cycling process.