Investigation on graphitic carbon foams – LiNiᵧPO₄ (y = 0.8–1.0) composites

By Lucangelo Dimesso,Christina Spanheimer, Wolfram Jaegermann
Published in Journal of Membrane Science NULL 2014

Abstract

Graphitic carbon foams coated with olivine-structured lithium nickel phosphate (LiNiᵧPO₄) (y = 0.8 -1.0) as possible cathode materials for 5 V applications are investigated. The composites are prepared by soaking the foams into solutions containing lithium, nickel ions and phosphates, treated in flowing air then in flowing nitrogen. The structural, morphological and electrochemical properties are strongly dependent upon the Ni-content. The X-ray diffractograms, performed on powders prepared under very similar conditions, showed the formation of LiNiPO₄ phase with Li₄P₂O₇ and Li₂Ni₃(P₂O₇)₂. The morphological investigation revealed a dramatic change of the layer by decreasing the Ni-content. The voltammetric curves show values of the mean peak maxima in the anodic region between 5.1 and 5.2 V and in the cathodic region between 4.88 for (y =1.0) and ∼5.18 V for (y = 0.9 and 0.8) respectively. The specific capacity of the composites (at the first cycle, a discharge rate of C/10 and room temperature) increases by decreasing the nickel content into the cathode material reaching a maximum of 122 mAhg⁻¹ for y = 0.8.

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