Alginate Fiber-Grafted Polyetheramine-Driven High Ion-Conductive and Flame-Retardant Separator and Solid Polymer Electrolyte for Lithium Metal Batteries

Abstract

Traditional polymer-based separators and solid polymer electrolytes (SPEs) often suffer from inherent poor flame retardancy and unsatisfied ionic conductivity, which seriously affect the safety and energy storage performance of lithium metal batteries (LMBs). Inspired by the mechanism of Li + conductivity, an alginate fiber (AF)-grafted polyetheramine (AF-PEA) separator with efficient Li + transport and excellent flame retardancy is dedicatedly designed, which also can act as the backbone for PEO-based SPEs (PEO@AF-PEA). Based on the intrinsic flame retardancy of the AF, the AF-PEA shows self-extinguishing ability, and its Li + transport ability (1.8 mS cm −1 at 25 °C) is enhanced by grafting the ion-conductive PEA chain segment. By simulating the transport and distribution of Li + in the AF-PEA, the PEA with 7-segment chain lengths can uniformly fill the Li + transport space between the alginate backbone to promote the Li + adsorption and the utilization of Li + anchoring points in PEA side chains, increasing the Li + transport rate and migration capacity. The LiFePO 4 /Li solid-state battery assembled using PEO@AF-PEA SPEs exhibits high safety and excellent cycling performance (exceeding 100 mAh g −1 after 1500 cycles at 2 C current density and 80 °C with less than 0.016% capacity decay for each cycle).

Designing polymer electrolytes for advanced solid lithium-ion batteries: recent advances and future perspectives

“…Other configurations also include block copolymers, 100 graft polymers, 101 star polymers, 102 etc. For example, block copolymers usually include soft segments and hard segments, in which the hard segments are used to increase the mechanical modulus, while the soft segment is used for lithium ion transmission.…”

Recent Progress in Flame-Retardant Polymer Electrolytes for Solid-State Lithium Metal Batteries

“…Wang et al synthesized an alginate fiber (AF)-grafted polyether amine (AF-PEA) diaphragm with high Li + transport efficiency and excellent flame readability (Figure 6a) [44]. The final PEO-based solid electrolyte was synthesized using AF-PEA as a skeleton (PEO@AF-PEA).…”

Flexible Solid-State Lithium-Ion Batteries: Materials and Structures

“…Solid electrolytes can be divided into two broad categories, solid polymer electrolytes (SPEs) and inorganic solid electrolytes (crystals, glass, ceramics, etc.) [76][77][78][79][80][81]. SPEs are more suitable for application in FLIBs due to their soft and flexible properties, low manufacturing cost, tunable chemical structure, and good electrode/electrolyte interface formation [82][83][84][85].…”