The invention relates to a high-capacity positive lead paste for a lead-acid battery and a preparation method of the high-capacity positive lead paste, and belongs to the technical field of lead-acid batteries, the high-capacity positive lead paste comprises the following raw materials in parts by weight: 100 parts of lead
powder, 5.5-7.2 parts of a high-capacity additive, 3.5-4.5 parts of red lead, 0.15-0.2 part of stannous mono-sulphate and 10-13 parts of
sulfuric acid; wherein the high-capacity additive takes a carbon
nano tube as a matrix, a large number of active groups are generated on the surface through
nitric acid treatment, the adsorbability of the carbon
nano tube is improved, the carbon
nano tube is activated, tri (N, N '-diisopropylformamido)
lanthanum is adsorbed and loaded in a liquid-phase environment by utilizing the adsorption characteristic of the carbon nano tube,
lanthanum doping is formed on an activated carrier after
roasting, and the high-capacity additive is prepared. Through hydrothermal and
roasting processes,
lead oxide and
lead sulfate form tetrabasic
lead sulfate composition on the surface of the doped carrier, and a stable
ion channel is formed in the positive
electrode active material, so that the battery has relatively high specific capacity and
cycling stability.