Bioinspired Separator with Ion-Selective Nanochannels for Lithium Metal Batteries

Abstract

The free transport of anions through commercial polyolefin separators used in lithium metal batteries (LMBs) gives rise to concentration polarization and rapid growth of lithium dendrites, leading to poor performance and short circuits. Here, a new poly(ethylene-co-acrylic acid) (EAA) separator with functional active sites (i.e., carboxyl groups) distributing along the pore surface was fabricated, forming bioinspired ion-conducting nanochannels within the separator. As the carboxyl groups effectively desolvated Li+ and immobilized anion, the as-prepared EAA separator selectively accelerated the transport of Li+ with transference number of Li+ (t Li + ) up to 0.67, which was further confirmed by molecular dynamics simulations. The battery with the EAA separator can be stably cycled over 500 h at 5 mA cm–2. The LMBs with the EAA separator have exceptional electrochemical performance of 107 mAh g–1 at 5 C and a capacity retention of 69% after 200 cycles. This work provides new commercializable separators toward dendrite-free LMBs.

A Li+-flux-homogenizing separator for long-term cycling of Li metal anodes

“…1a). Compared with other published composite separators, 17,28–36 the PVDF-HFP/SN separator-based cell maintains a durable operation lifespan and high capacity retention, as shown in Fig. 1b and Table S1 (ESI†).…”

Highly crystalline covalent triazine frameworks modified separator for lithium metal batteries

“…To evaluate the selective transport ability of Li + for different separators, the , representing the ratio of Li + mobility to total ionic mobility, was evaluated using the Bruce-Vincent method [40] . The chronoamperometry profiles of HC-CTF-PE and AM-CTF-PE assembled Li//Li symmetric cells are present in Figure 4D and E.…”

Polyhedral Oligomeric Silsesquioxane Modified Polyolefin Separator for Advanced Lithium–Metal Batteries

“…Among them, the introduction of functional nanomaterials such as GO, MoS 2 , or MXene on the surface of polyethylene (PE) is considered to be a simple and effective solution to solve the above issues. As a result of the abundance of polar functional groups on the surface of these nanoparticles, such as hydroxyl, carboxyl, and amino groups, the wettability of the separator to the electrolyte can be significantly enhanced, which is beneficial to the transmission of lithium ions between the two electrodes, and simultaneously makes the distribution and nucleation of metal ions on the lithium electrode surface more uniform, consequently, effectively mitigating the safety issues originating from the random growth of lithium dendrites . However, the biggest problem with this method is that nanoparticles with large flake structures can easily aggregate and block the pore structure of the polyolefin separator, hindering lithium-ion transport.…”