Study On Cathode Material EMD Of Li-MnO₂ Batteries And Its Application

Li-MnO₂ battery has some merits as follows: high working voltage and specificenergy, wide working temperature range, low spontaneous discharge rate, goodleaking resistance, safe and has no pollution and so on. So it's the most familiar one ofprimary lithium batteries and having the most output. The battery cathode materialshave been studied hotly for long time. Studies were done in this paper on EMDphysicochemical and structural changes after being thermally treated and relation ofthose changes with battery performances.EMD for no mercury alkaline zinc manganese dioxide battery specially was usedas cathode material for Li-MnO₂ ones and heated for 14 or 20 hours at 300℃,350℃,380℃,400℃ and 420℃ respectively. To those samples, SEM was used to studychanges of particle size and appearance. And tests were done on accumulate density,BET surface area, electrolyte absorbing quantity and MnO₂ content. And change ofwater content in EMD powder during heating was studied by DTA and TG methods.Also, XRD was used to study crystal structure and size, crystallographic componentsand lattice constant.Batteries were prepared with those EMD samples and tested of open circuitvoltage, short circuit current and A-c essential resistance. Discharge Performances ofbatteries were tested on low or mild and high power output conditions, includingunder 62ohm load and at 45 mA-cont, 1000mA-cont and 900mA pulse. Some of thosetests were also done on batteries reserved at normal temperature for one and sixmonths respectively.Through those experiments, rules were obtained that how EMD physicochemicaland crystal structure changes affected battery discharge and storage performances.And optimal condition of EMD heattreatment was ascertained. Batteries which wereused on high power output occasions showed best discharge performance with EMDheated at about 380℃. Contrarily, EMD should heated at 400℃or so for thosebatteries used on mild or low power output occasions. And it seemed better for EMDtreated for 20 hours or so. CR435 pine type battery was prepared with EMD treatedaccording as those conclusions, and performances were tested. The mainelectro-performances achieved or exceed those of overseas BR435 ones.