Microporous Cellulose/PVDF-HFP membrane for lithium ion batteries by phase inversion method

What is it about?

PVDF and PVDF-HFP membranes also have their own disadvantages, i.e. low thermal stability, poor electrochemical stability, low cyclic and rate performances, which limits the wide applications in lithium ion battery. we add hydrophilic cellulose to eleimnate the above issues in separator of PVDF-HFP.

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Why is it important?

The porous Cellulose/PVDF-HFP blending membrane is successfully prepared via phase inversion method in this work. With the addition of cellulose, the membrane porosity is improved from 40% (pure PVDF-HFP) to 85% (with the optimal cellulose content, 30 wt %), meanwhile, the electrolyte uptake is enhanced from 170% to 310%, thus leading to a high ion conductivity of 1.89 mS cm−1. Lithium transference number for Cellulose/PVDF-HFP (3/7) is 0.89. In addition, the superior electrochemical and thermal stability of the membrane have been confirmed by the wide electrochemical window (5.35 V) and low shrinkage at high temperatures. The battery assembled with the composition-optimized membrane can offer a high capacity of 171.1 mAh g−1 and 91.6% of the initial capacity can be maintained even after 100 cycles. Experimental results clearly prove this type of membrane is able to improve the discharge capacity, cycling and rate performances of LIBs.

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