New lithium ion batteries exploiting conversion/alloying anode and LiFe_0.25Mn_0.5Co_0.25PO₄ olivine cathode

Highlights: • New Li-ion batteries are reported. • LiFe_0.25Mn_0.5Co_0.25PO₄ olivine is used as the cathode. • Either Sn-C or Sn-Fe₂O₃-C composites are used as anodes. • The electrode/electrolyte interfaces are monitored by EIS. • The systems are considered suitable for energy storage - Abstract: New Li-ion cells are formed by combining a LiFe_0.25Mn_0.5Co_0.25PO₄ olivine cathode either with Sn-Fe₂O₃-C or with Sn-C composite anodes. These active materials exhibit electrochemical properties very attractive in view of practical use, including the higher working voltage of the LiFe_0.25Mn_0.5Co_0.25PO₄ cathode with respect to conventional LiFePO₄, as well as the remarkable capacity and rate capability of Sn-Fe₂O₃-C and Sn-C anodes. The stable electrode/electrolyte interfaces, demonstrated by electrochemical impedance spectroscopy, along with proper mass balancing and anode pre-lithiation, allow stable galvanostatic cycling of the full cells. The two batteries, namely Sn-Fe₂O₃-C/LiFe_0.25Mn_0.5Co_0.25PO₄ and Sn-C/LiFe_0.25Mn_0.5Co_0.25PO₄, reversibly operate revealing promising electrochemical features in terms of delivered capacity, working voltage and stability, thus suggesting these electrodes combinations as suitable alternatives for an efficient energy storage.