Red phosphorus is a potential anode material for lithium-ion and sodium-ion batteries, but like sodium itself, its positive values are counter-balanced by considerable challenges.

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Academics in China and Poland have done a detailed systematic review of phosphorus anode research, which has been published for anyone to read.

“The development of cost-effective and high-performance red phosphorus anode materials for Li-ion and Na-ion batteries is imperative,” said review co-author Professor Hailei Zhao, of the University of Science and Technology Beijing. “Despite red phosphorus showing great potential, the inherent poor electrical conductivity and significant volume changes during charge-discharge compromise its cycling stability.”

She puts the conductivity at ~10-14S/cm and the volume change at 300%, explaining that these cause substantial electrode polarisation, sluggish reaction kinetics and electrode pulverization.

One potential solution is a high-conductivity support structure with plenty of internal volume to accommodate the swelling phosphorus, if one can be engineered.