The invention provides negative electrode slurry of a lithium ion battery, a positive electrode of the lithium ion battery prepared by using the slurry, and the battery. The negative electrode slurry comprises a negative-electrode active material, a bonding agent, a solvent and a pore-forming agent, wherein the pore-forming agent is selected from one or more in azo-compound and / or sulfonylhydrazine compound. The slurry, the positive electrode and the battery have the advantages that under the condition of guaranteeing no reduction of the compaction density of a negative electrode piece, the porosity of the electrode piece can be increased, the uniformity of pore distribution is increased, the effective area of a liquid phase for conducting lithium ions is improved, the high energy density of the battery is guaranteed, simultaneously the rate capability and the low-temperature performance of the battery are improved and simultaneously the capacity is also improved.