The electrochemical reactivity of the NiP3 skutterudite-type phase with lithium

We report the electrochemical Li reactivity of the cubic NiP3 phase, a candidate for anode applications for Li-ion batteries. NiP3 reacts with nine lithium per formula unit leading to a first cycle reversible capacity of 1,475 mAh/g at an average potential of 0.9 V vs. Li+/Li degrees. Electrochemical measurements and complementary X-ray diffraction showed that NiP3 presents a conversion process (NiP3+9Li(+)+9e(-) -> Ni degrees + 3Li(3)P) competing with an insertion process. A good cycleability may only be obtained on a limited potential window, excluding the low-potential region.