Blending of hard and soft organic–inorganic hybrids for use as an effective electrolyte membrane in lithium-ion batteries

• A new blend electrolyte is prepared by blending of two organic–inorganic hybrids.
• The blend electrolyte exhibits a maximum ionic conductivity value of 6.9 mS cm−1.
• The blend electrolyte is electrochemically stable up to 5 V.
• The test cell exhibits an initial discharge capacity of 150 mA h g−1 at 0.2 C.
• The test cell shows good cycling performance of over 200 cycles.

In this study, two unique organic–inorganic hybrids are synthesized and optimized to obtain a new type of hybrid blend membrane. A soft hybrid is obtained from reaction of polyetheramine (M-2070) and (3-glycidyloxypropyl)trimethoxysilane (GLYMO), whereas a hard hybrid is prepared from reactions of polyetherdiamine (ED2003), poly(ethylene glycol) diglycidyl ether (PEGDGE) and GLYMO. Both hybrids are finally blended with poly(vinylidene fluoride-co-hexafluoropropylene) (P(VdF-HFP)) to get the hybrid blend membrane and plasticized with 1 M LiPF6 in EC/DEC. The successful synthesis of the hybrid blend membrane structure is established from 13C and 29Si solid-state NMR spectroscopy. FTIR results reveal the interactions of different groups of the hybrid blend membrane. The hybrid blend electrolyte possesses maximum ionic conductivity value of 6.9 mS cm−1 at 30 °C and is electrochemically stable up to 5 V. The electrochemical performance of the hybrid blend electrolyte assemble in a battery cell with the LiFePO4 cathode exhibits a good cycle life of over 200 cycles with an initial discharge capacity of 150 mA h g−1. In addition, coulombic efficiency of 97–99% is maintained for the whole cycles. Our results demonstrate that the present hybrid blend electrolyte can be a potential candidate serving as an effective electrolyte in lithium-ion batteries.

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