Lithium ion battery and preparation method thereof

The invention provides a lithium ion battery and a preparation method thereof. The lithium ion battery comprises a positive electrode, a negative electrode and an electrolyte, a positive electrode active material in the positive electrode comprises a nickel cobalt lithium manganate polycrystalline material and a nickel cobalt lithium manganate single crystal material, a binder in the negative electrode comprises a polyacrylic acid binder, the cycle performance of the battery is improved, and meanwhile, the energy density of the battery at low temperature is improved. 本发明提供了一种锂离子电池及其制备方法，所述锂离子电池包括正极、负极和电解液，所述正极中的正极活性物质包括镍钴锰酸锂多晶材料和镍钴锰酸锂单晶材料，所述负极中的粘结剂包括聚丙烯酸类粘结剂，在改善电池循环性能的同时提高低温下电池的能量密度。