A Protein‐Based Janus Separator for Trapping Polysulfides and Regulating Ion Transport in Lithium−Sulfur Batteries

Abstract

LithiumÀ sulfur (LiÀ S) batteries are a promising candidate for the next-generation energy storage system, yet their commercialization is primarily hindered by polysulfide shuttling and uncontrollable Li dendrite growth. Here, a protein-based Janus separator was designed and fabricated for suppressing both the shuttle effect and dendrite growth, while facilitating the Li + transport. The Li metal-protecting layer was a protein/MoS 2 nanofabric with high ionic conductivity and good Li + affinity, thus capable of homogenizing the Li + flux and facilitating the Li + transport. The polysulfide-trapping layer was a conductive protein nanofabric enabling strong chemical/electrostatic interactions with polysulfides. Combination of the two layers was achieved by an integrated electrospinning method, yielding a robust and integral Janus separator. As a result, a long-lived symmetric Li j Li cell (> 700 h) with stable cycling performance was demonstrated. More significantly, the resulting LiÀ S battery delivered greatly improved electrochemical performance, including excellent rate capacity and remarkable cycle stability (with a low decay rate of 0.063 % per cycle at 0.5 A g À 1 over 500 cycles). This study demonstrates the effectiveness of the Janus separator configurations for simultaneously addressing the shuttle effect and dendrite growth issues of LiÀ S batteries and broadens the applications of electrospinning in electrochemistry community.

Adaptively Reforming Natural Enzyme to Activate Catalytic Microenvironment for Polysulfide Conversion in Lithium–Sulfur Batteries

“…Especially, when DHcs is introduced, battery capacities of 1472.1, 996.6, 898.6, 858.5, and 817.0 mAh g –1 are achieved at 0.2, 0.5, 0.8, 1.0, and 1.5 C, respectively, which are superior to those of its counterparts and most of the other reported protein materials (Figure S20). ,− When the current density is abruptly reduced back to 0.2 C, the capacity of CNTs-S/DHcs cathode remains close to that of the previous cycles at the same rate, illustrating the excellent reaction reversibility.…”

Highly Elastic and Polar Block Polymer Binder Enabling Accommodation of Volume Change and Confinement of Polysulfide for High-Performance Lithium–Sulfur Batteries

“…To further figure out what accounts for superior battery performance, electrochemical impedance spectroscopy (EIS) measurements were performed to determine the Li + conductivity of cells with different binders within the frequency range of 0.1 Hz to 2 MHz. The Nyquist plot consisted of a semicircle at high frequencies and an inclined line in the low-frequency region . The diameter of the semicircle represented the charge transfer resistance ( R ct ) .…”

“…The Nyquist plot consisted of a semicircle at high frequencies and an inclined line in the low-frequency region. 37 The diameter of the semicircle represented the charge transfer resistance (R ct ). 38 In addition to effectively trapping the dissolved LiPSs, the FBCP binder can also reduce the Li + transport resistance.…”

A separator modified by barium titanate with macroscopic polarization electric field for high-performance lithium–sulfur batteries

“…Conversely, the separators modified with functional materials adjacent to the sulfur cathode can efficiently inhibit the shuttling of polysulfides to the lithium anode by crossing the separator. 9–12…”

“…Conversely, the separa-tors modified with functional materials adjacent to the sulfur cathode can efficiently inhibit the shuttling of polysulfides to the lithium anode by crossing the separator. [9][10][11][12] Porous carbon nanotubes and graphene, as typical carbon materials, have been employed as carbon matrices of functional separators due to their electrical conductivity. Nevertheless, they failed to achieve the desired capability to prevent the shuttling of polysulfides in view of the insufficient van der Waals adsorption between carbonaceous materials and polysulfides.…”