Self-Assembly of PEI/SiO2 on Polyethylene Separators for Li-Ion Batteries with Enhanced Rate Capability
2015 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, no 5, 3314-3322 p.Article in journal (Refereed) Published
A simple and environmentally friendly self-assembly process of oppositely charged polymer PEI and inorganic oxide SiO2 was demonstrated for the construction of an ultrathin layer on the surface of PE separator. The XPS, FT-IR, SEM, and EDS characterizations give clear evidence of the successful self-assembly of PEI and SiO2 without significantly increasing the thickness and sacrificing the pristine porous structure of PE separator. This process improves a variety of crucial properties of PE separator such as the electrolyte wetting, the electrolyte uptake, the thermal stability, the ionic conductivity, Li+ transference number, the electrochemical stability and the compatibility with lithium electrode, endowing lithium-ion battery (Li as anode and LiCoO2 as cathode) with excellent capacity retention at high C-rates and superior cycling performance. At the current density of 5 C, the cell with PE separator almost loses all the capacity. In contrast, the cell with (PEI/SiO2)-modified PE separator still holds 45.2% of the discharge capacity at 0.2 C. The stabilized SEI formation and high Li+ transference number of (PEI/SiO2)-modified PE separator were interpreted to be the substantial reasons leading to the remarkably enhanced battery performance, rendering some new insights into the role of the separator in lithium-ion batteries.
Place, publisher, year, edition, pages
2015. Vol. 7, no 5, 3314-3322 p.
Li-ion battery, rate capabiity, separator, surface modification, self-assembly
Chemical Sciences Nano Technology
IdentifiersURN: urn:nbn:se:uu:diva-248189DOI: 10.1021/am508149nISI: 000349580800038PubMedID: 25602261OAI: oai:DiVA.org:uu-248189DiVA: diva2:802321