Magnesium Borate Fiber Coating Separators with High Lithium‐Ion Transference Number for Lithium‐Ion Batteries

Abstract

In this work, magnesium borate fiber (MBO) is used as a functional ceramic to coat onto a polypropylene (PP) separator (MBO@PP). This MBO coating layer increases the lithium‐ion transference number (tLi+) from 0.24 to 0.57 in the LiPF6‐based electrolyte due to the MBO acting as Lewis acid sites interacts with Lewis base PFbold6- . The increase in the tLi+ reduces the concentration polarization and promotes the migration of lithium ions. Besides, the prepared MBO@PP separator has better wettability with liquid electrolyte, the electrolyte uptake as well as thermal stability. The LiFePO4 half‐coin with MBO@PP separator not only had better cycle stability, but also had a higher capacity retention rate at high current.

Facile Fabrication of Functionalized Separators for Lithium-Ion Batteries with Ionic Conduction Path Modifications via the γ-Ray Co-irradiation Grafting Process

“…This indicates that lithium ions contribute more to the ionic conduction and benefit in achieving a fast electrochemical reaction. The increase in the lithium-ion transference number promotes the electrochemical reaction of LIBs and reduces the concentration polarization. , Lithium ions are easier to transport and therefore have a higher discharge capacity. A similar situation can also be found from the corresponding capacity–voltage curve (Figure b,c).…”

“…Besides ensuring safety, it is also an effective strategy to improve the electrochemical performance of the battery by simply introducing some functional compounds as a coating layer on the separator . We coated the PP separators with a layer of magnesium borate fiber (MBO) as a functional ceramic, where MBO acts as a Lewis acid and coordinates with anions in the electrolyte; thereby, the movement of anions was restricted and the lithium-ion transference number could be increased to 0.57 . By the coating modification of the separator, the real lithium ionic conductivity was improved and the kinetics of liquid transport was accelerated.…”

“…9 We coated the PP separators with a layer of magnesium borate fiber (MBO) as a functional ceramic, where MBO acts as a Lewis acid and coordinates with anions in the electrolyte; thereby, the movement of anions was restricted and the lithium-ion transference number could be increased to 0.57. 19 By the coating modification of the separator, the real lithium ionic conductivity was improved and the kinetics of liquid transport was accelerated. Wang et al 20 used plasma treatment to build an ultrathin poly(acrylic acid) (PAA) and ZrO 2 composite-functional-modified film on a PE separator.…”

Bistrifluoroacetamide‐Activated Double‐Layer Composite Solid Electrolyte for Dendrite‐Free Lithium Metal Battery

“…However, this type of electrolytes is not only complicated to synthesize, but also generally has low conductivity. [ 30–34 ]…”

“…However, this type of electrolytes is not only complicated to synthesize, but also generally has low conductivity. [30][31][32][33][34] In this work, we reported the development of a novel bistrifluoroacetamide (BTFA) activated double-layer composite solid electrolyte (named as BTFA-DSE) for lithium metal battery, equipped with PEO electrolyte at anode side, "polymer in ceramic" type PVDF-LATP (3:7, weight ratio) at cathode side, and both are activated by BTFA polar molecular plasticizer. The rational design of the dual-layer structure ensures the mechanical strength of the electrolyte and the availability of high-voltage cathodes.…”