Galaxy Note 7 battery chemistry could be behind recall, says expert

Metal impurities or a change in the electrolyte systemcould be what's causing Galaxy Note 7 batteries to explode, forcing Samsung to issue a global recall of its newest smartphone, according to an expert.

"There are a number of things that can go wrong with high energy density lithium-ion cells that are operated at higher voltages being used in modern phones," saidDalhousie University professor JeffDahn.

Heis a pioneer in the development of the lithium-ion batteries used incellphonesand automobiles.

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Dahn said if there are metal impurities in the positive electrode, they can dissolve and create internal short circuits in the cell.If Samsung has changed the electrolyte system, that could also lead to problems, he added.

It's not that Samsunghas reachedthe limit of what it can do withlithium-ion batteries, said Dahn.In fact, he said the lithium-ion hasn't been used to its full potential.

"Other lithium-ion cells used by, for example Apple, have similar characteristics to the Samsung cells, but they're clearly not having the same issues. So I think there's just something weird with the chemistry in those new Note 7 cells."

Dahn said lithium-ion batteries are perfectly safe, and it's unusual Samsung is having this problem.

"There's billions and billions and billions of lithium-ion cells in use across the world, and the vast majority are perfectly safe without any issues," he said.

Dahn noted that any lithium-ion batteries released for consumers haveto gothrough a "huge number" of safety tests in order to be certified for use.