Complex and confusing are two words that often come to mind when attempting to describe some of the breakthrough battery technology that has surfaced in recent times. Seemingly every new type of technology boasts, at least in some way, benefits over the batteries that are used in hybrids and electric vehicles today. Adding to the confusion is the fact that most battery developers like to present specs using different methods. With that bit of foreshadowing out of the way, it's time to delve into the proposed benefits of a new synthesized pyrophosphate compound (Li2FeP2O7) developed for use as a cathode material in li-ion batteries.

A team from the University of Tokyo and the Tokyo Institute of Technology has synthesized the new pyrophosphate compound by a conventional solid-state reaction. For the science wizzes out there, Green Car Congress points that the new cathode material has:
A reversible electrode operation at around 3.5 V vs. Li was identified with the capacity of one-electron theoretical value of 110 mAh g-1 even for one micrometer particles without any special efforts such as nanosizing or carbon coating. The material showed steady capacity retention upon cycling, but the initial charge curve showed a different shape from that of subsequent cycles, possibly due to the irreversible structural change. About 40 percent of the initial capacity can be delivered in one hour (1C rate), and about 20 percent in six minutes (10C rate), suggesting that such electrodes could sustain respectable rate capabilities.
For us more common folk, the numbers indicate that the new pyrophosphate Li2FeP2O7 offers the highest claimed voltage among the known iron-based phosphate cathodes and could potentially yield higher performance than lithium iron phosphate (LiFePO4 or LFP batteries), which is widely accepted as the most promising cathode material for lithium-ion batteries utilized in automotive applications. Of course, this synthesized cathode material is in its infancy, but with its promising numbers, Li2FeP2O7 could become the material of choice for the next (or next-next) generation of plug-in vehicles.

[Source: Green Car Congress]

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