Nanocellulose Modified Polyethylene Separators for Lithium Metal Batteries

Abstract

Poor cycling stability and safety concerns regarding lithium (Li) metal anodes are two major issues preventing the commercialization of high-energy density Li metal-based batteries. Herein, a novel tri-layer separator design that significantly enhances the cycling stability and safety of Li metal-based batteries is presented. A thin, thermally stable, flexible, and hydrophilic cellulose nanofiber layer, produced using a straightforward paper-making process, is directly laminated on each side of a plasma-treated polyethylene (PE) separator. The 2.5 µm thick, mesoporous (≈20 nm average pore size) cellulose nanofiber layer stabilizes the Li metal anodes by generating a uniform Li flux toward the electrode through its homogenous nanochannels, leading to improved cycling stability. As the tri-layer separator maintains its dimensional stability even at 200 °C when the internal PE layer is melted and blocks the ion transport through the separator, the separator also provides an effective thermal shutdown function. The present nanocellulose-based tri-layer separator design thus significantly facilitates the realization of high-energy density Li metal-based batteries.

Stabilizing lithium metal anode by octaphenyl polyoxyethylene-lithium complexation

“…Issues resulted from dendritic lithium deposition, infinite volume change, and unstable solid-electrolyte interface (SEI) layers all contribute to the impracticality of lithium metal batteries [2][3][4] . Over the past several decades, researchers have developed various strategies to counteract these obstacles, including replacing Li metal with a LiX alloy 5 , developing new solid electrolytes or optimizing electrolyte components [6][7][8][9] , modifying separators [10][11][12][13] , constructing an artificial upper interfacial layer for Li metal anodes [14][15][16][17][18] , designing two-dimensional/three-dimensional (2-D/3-D) Lihosting materials 4,[19][20][21] , and various other techniques 22 .…”

Coupling a Sponge Metal Fibers Skeleton with In Situ Surface Engineering to Achieve Advanced Electrodes for Flexible Lithium–Sulfur Batteries

“…[ 6–9 ] Among the next‐generation candidates, lithium–sulfur batteries (LSBs) show great promise due to their low gravimetric densities (Li: 0.534 g cm −3 ; S: 2.07 g cm −3 ), large theoretical capacities (Li: 3860 mA h g −1 ; S: 1675 mA h g −1 ), and high energy density (2600 W h kg −1 ). [ 10–14 ] Despite these remarkable advantages, the commercialization of LSBs is still challenged by several issues on Li metal anodes and S cathodes, and thereby blocking access to the market: i) uncontrollable Li dendrite growth owing to uneven current density during repeated deposition and dissolution, causing short lifespan and even safety hazards; [ 15,16 ] ii) unstable solid electrolyte interface (SEI) layer with periodic breakage and regeneration during continuous plating/stripping, which will bring about poor ion transport and large interfacial impedance; [ 17–19 ] iii) a large excess (over 100% oversize) of Li metal with low depth of discharge, which is far from sustainable targets for commercialization; [ 17,20,21 ] iv) intrinsic insulating nature of S and Li 2 S, resulting in insufficient utilization of active material; [ 22,23 ] v) dissolution of intermediate lithium polysulfides, which leads to notorious shuttle effect and thus sluggish reaction kinetics; [ 24,25 ] and vi) huge volume expansion both in Li anode (infinite) and S cathode (≈80%) during cycling process. [ 23 ] Given all that, it is highly desirable to keep plugging away at developing stable LSBs by rationally designing anodes and cathodes, respectively.…”

“…Whereas, the high reactivity of Li metal and interfacial resistance with alien layers still prohibit its further development. [ 14,21 ] Recently, our group reported another brand new example of a spray quenching (SQ) method to in situ construct an organic–inorganic composite SEI on molten Li with high ion conductivity and mechanical durability. [ 17 ] It has been verified that this strategy can effectively suppress the dendrite growth and enhance the integrality of electrodes.…”

Nanocellulose in Biotechnology and Medicine: Focus on Skin Tissue Engineering and Wound Healing

“…Nanocellulose/polypyrrole [111] Nanocellulose/polyethylene [112] Graphene/nanocellulose/silicon [113] Solar cells/panels Nanofibers from sisal with graphene oxide [73] (Super)capacitors Bacterial nanocellulose/carbon nanotubes/triblock-copolymer ion gels [114] Nanocellulose with polyaniline [115] Acoustics Membranes for loudspeakers Cellulose nanofibers with Fe3O4 nanoparticles [71] (Bio)sensors Optical SERSbased Detection of pesticides, dyes, bacteria [116,117] Optical fluorescencebased Detection of heavy metals [118] Detection of thiols [119] Detection of elastase [120] Chemical Detection of vapors (NH3.H2O, H2O, HCl, acetic acid) [16] Electrochemical Detection of cations in biological fluids (Na + , K + , Ca 2+ ) [38] Detection of cholesterol [121] Detection of avian leukosis virus [122] Piezoelectric Based on bacterial cellulose [123] Based on plant-derived cellulose nanofibrils [124] Based on nanocellulose with chitosan [125] Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 14 December 2018 Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 14 December 2018 doi:10.20944/preprints201812.0170.v1…”