Influence of a Liquid Electrolyte on Electronic and Ionic Transfers in a LiNi_0.5Mn_0.3Co_0.2O₂/Poly(vinylidene Fluoride-co-hexafluoropropylene)-Based Composite Material

Abstract

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Charge Transport Limitations to the Power Performance of LiNi0.5Mn0.3Co0.2O2 Composite Electrodes with Carbon Nanotubes

“…This value is close to the activation energy measured for the electronic conductivity of NMC soaked within LP30 electrolyte, 0.23 eV. 27 This similarity of values suggests that the polarization resistance (at 100% SOC) is limited by the electrons transfers in the electrode, and that it is itself limited by the electronic conductivity of the active material. The calculation of the effective electronic conductivity of the electrodes from the polarization resistance and the comparison with the electronic conductivity of an NMC pellet soaked within LP30 electrolyte shows that the conducting additives improve the electronic transfers within the composite electrode and that the CNTs are more efficient than CB on this point, particularly at 0 °C and 40 °C (Table SII).…”

“…The stoichiometry, structure and electrical properties of this material are reported elsewhere. 26,27 Before the dispersion process the initial size of the CNT powder varies between 70 and 790 μm. Average external diameter of the carbon nanotubes constituting the CNT balls is between 4 and 30 nm.…”

“…43 It is known that the electronic conductivity in the NMC phase is limited at the grain boundaries within the clusters and at contact points between clusters. 27 Even if the carbon-binder phase does not percolate, it can significantly improve the electrode electronic conductivity by forming gateways between NMC clusters, thus minimizing the constriction resistances at contact points between them, 42 and by short-circuiting the grain boundaries at the surface of the NMC clusters. 26 In this way, as seen in Fig.…”

Carbon black/electrolyte interface study by electromagnetic and electrochemical techniques in γAl2O3/poly(vinylidene fluoride)/carbon black composite materials: Application for lithium-ion batteries

“…impregnated electrode. 6,11,12,13,14 One must also consider the role of interfaces (adsorption of ions to the surface of active material and carbon particles), and the subsequent physical interactions at these interfaces. 6,9,10 The conductivity of the wet electrode drops as compared to the dry electrode due to the nanometric size of the carbon black particles that leads to a particularly high specific surface area.…”