Polydopamine-coated cellulose microfibrillated membrane as high performance lithium-ion battery separator

Eco-friendly cellulose microfibers were modified by mussel-inspired polydopamine coating layer and a cellulose/polydopamine (CPD) membrane was fabricated by a facile and cost-effective papermaking process. It was demonstrated that CPD membrane possessed a compact porous structure, superior mechanical strength and excellent thermal dimensional stability. CPD membrane was explored as a lithium-ion battery separator with its superior mechanical strength, low-cost and favorable electrochemical properties. Lithium cobalt oxide/graphite cell using CPD separator displayed the best cycling stability and rate capability compared with those of commercialized polypropylene separator and pristine cellulose separator. Furthermore, alternating-current impedance of the cell with CPD separator presented minor variation of 9 Ω after the 100th cycle indicating an excellent interfacial stability of the cell. These excellent performances could endow CPD membrane as a very promising application as a high performance lithium-ion battery separator.