An Ultra-Long-Life Flexible Lithium–Sulfur Battery with Lithium Cloth Anode and Polysulfone-Functionalized Separator

Abstract

Flexible and high-performance batteries are urgently required for powering flexible/wearable electronics. Lithium−sulfur batteries with a very high energy density are a promising candidate for high-energy-density flexible power source. Here, we report flexible lithium−sulfur full cells consisting of ultrastable lithium cloth anodes, polysulfone-functionalized separators, and freestanding sulfur/graphene/boron nitride nanosheet cathodes. The carbon cloth decorated with lithiophilic three-dimensional MnO 2 nanosheets not only provides the lithium anodes with an excellent flexibility but also limits the growth of the lithium dendrites during cycling, as revealed by theoretical calculations. Commercial separators are functionalized with polysulfone (PSU) via a phase inversion strategy, resulting in an improved thermal stability and smaller pore size. Due to the synergistic effect of the PSU-functionalized separators and boron nitride−graphene interlayers, the shuttle of the polysulfides is significantly inhibited. Because of successful control of the shuttle effect and dendrite formation, the flexible lithium−sulfur full cells exhibit excellent mechanical flexibility and outstanding electrochemical performance, which shows a superlong lifetime of 800 cycles in the folded state and a high areal capacity of 5.13 mAh cm −2 . We envision that the flexible strategy presented herein holds promise as a versatile and scalable platform for large-scale development of high-performance flexible batteries.

Regulating Coordination Environment in Metal–Organic Frameworks for Adsorption and Redox Conversion of Polysulfides in Lithium–Sulfur Batteries

“…The decomposition barrier of Li 2 S was also investigated. The calculated decomposition energy curves in Figure e and the corresponding decomposition path (Figure S34 in the Supporting Information) show that Li 2 S experience a lower decomposition energy barrier on the surface of Bi-MOF (0.37 eV) than graphene (0.81 eV), suggesting that Bi-MOF can promote the delithiation kinetics of Li 2 S, which corresponds well with the shifted CV curves in Figure f and higher Coulombic efficiency of the LSBs …”

“…The calculated decomposition energy curves in Figure 5e and the corresponding decomposition path (Figure S34 in the Supporting Information) show that Li 2 S experience a lower decomposition energy barrier on the surface of Bi-MOF (0.37 eV) than graphene (0.81 eV), suggesting that Bi-MOF can promote the delithiation kinetics of Li 2 S, which corresponds well with the shifted CV curves in Figure 2f and higher Coulombic efficiency of the LSBs. 49 The Gibbs free energy from S to Li 2 S on metal clusters of Bi-MOF-1 and rGO were calculated and compared to value the electrocatalytic effect of Bi-MOF-1. The calculated Gibbs freeenergy diagrams in Figure 5f indicate that the entire conversion process from S 8 to Li 2 S is spontaneous and almost thermodynamically equivalent.…”

Multifunctional Protection Layers via a Self-Driven Chemical Reaction To Stabilize Lithium Metal Anodes

“…It has also a high capacity retention of up to 78% (after 310 cycles). In addition, the Li–S pouch-type battery based on the LiF/Li x LLTO-Li anode, Co 9 S 8 @MoS 2 /CNF interlayer, and CNT/S cathode achieves a high volumetric energy density of 478 Wh L –1 (higher than that reported previously) (Figure e). ,− The volumetric energy density is calculated based on the total volume of the battery, and the detailed parameters are listed in Table S2 in the Supporting Information. To exceed the energy density limit of 300 Wh kg –1 for LIBs, the NCM811 cathode was paired with the LiF/Li x LLTO-Li anode for a more realistic pouch battery system (Figures S20 and S21 in the Supporting Information).…”

“…(c) Six LEDs are lit up by the Li–S pouch-type battery under different states. (d) Long-term cycle stability of the pouch-type Li–S battery using the LiF/Li x LLTO-Li anode, CNT/S cathode, and 1 M LiTFSI in 1:1 vol/vol DOL/DME electrolyte, and the operating voltage window was 1.7–2.8 V. (e) Volumetric energy density of the pouch-type cell compared with the data from literature studies. ,− …”

Functionalized 12 µm Polyethylene Separator to Realize Dendrite‐Free Lithium Deposition toward Highly Stable Lithium‐Metal Batteries

“…The cross‐section scanning electron microscope (SEM) and atomic force microscopy (AFM) images in Figure 2 a ; and Figure S2f,g (Supporting Information) show the compact sandwich structure of the TV‐PE film, while its surface is quite flat and well wrapped with the rGO sheets (Figure 2b–e ), which is favorable for uniform electrolyte and ion flux distribution. [ 18 ] The original PE membrane possesses a porous structure with uneven distribution of macrochannels between 100 and 200 nm (Figure 2f ). It should be noted that after TV‐layer modification, the mass transport realizes mainly through the meso‐channels and microchannels formed in the functional layer, which could greatly facilitate the mass transport.…”