Diphenylamine: A safety electrolyte additive for reversible overcharge protection of 3.6V-class lithium ion batteries

A polymerizable monomer , diphenylamine (DPAn), is reported to act as a safety electrolyte additive for overcharge protection of 3.6 V-class lithium ion batteries . The experimental results demonstrated that the DPAn monomer could be electro-polymerized to form a conductive polymer bridging between the cathode and anode of the battery , and to produce an internal current bypass to prevent the batteries from voltage runaway during overcharge. The charge–discharge tests of practical LiFePO 4 /C batteries indicated that the DPAn additive could clamp the cell's voltage at the safe value less than 3.7 V even at the high rate overcharge of 3 C current, meanwhile, this monomer molecule has no significant impact on the charge–discharge performance of the batteries at normal charge–discharge condition.