The Application Of Hard Carbononthe Anode Oflithium-Ion Battery

Lithium ion batterypossessesmany unique advantages, such as long cycle life, no memory effect, high specific energy, etc. It plays a more and more important role in people’s life.Lithium ion battery has been widely used in consumer electronic products, such as mobile phone, digital camera, portable notebook computer. At the same time, lithium ion battery is considered to be an ideal power source for electric vehicle.The anode material, an important part of lithium ion battery, affects the performance of lithium ion battery. At present, graphite is dominant on the market. However, the poor low temperature performance of graphite anode and easily produceing lithium dendrites on the anode surface, and other problemshindered the development and expansion of application scope of lithium ion battery. Under this background, this dissertation focuses on the application of hard carbon materials as anode in lithium ion battery. Hard carbon was mixed with graphite to prepare composite anode materials. hard carbon/graphite hybrid technology, as well as the performance of lithium ion battery using carbon/graphite composite as anode are studied in detail, including the following two parts:(1) Firstly, the physical properties of hard carbon and graphite were characterized in detail. ICP results showed that the content of metal impurities in two materials are rarely, below10ppm, achieves the requirements of industrial production of lithium ion battery. Different proportion of graphite and hard carbon are mixed, the physical and electrical properties of the slurry and the negative plate were studied, which determined that the optimal mixing ratio of hard carbon is15%.(2) The hard carbon/graphite (15%:85%) composite material is used as anode to prepare experimental lithium ion battery, while using pure graphite as anode to prepare the contrast test batteries. a series ofelectronic properties were tested to the experimental battery and contrast battery. The results showed that the capacity of experimental battery was lower than the contrast battery, due to the lower first charging efficiency of hard carbon. However, other properties of experimental battery were far better than the contrast battery, such asthe charge ability at low temperature, pulse charge and discharge power, high temperature storage and different temperature cycling, especially the low temperature charge performance.The composite material can effectively prevent the formation of lithium dendrite. Therefore, the composite material exhibit better properties than the pure graphite material.