Elsevier

Energy Storage Materials

Volume 14, September 2018, Pages 258-266
Energy Storage Materials

Nanoporous and lyophilic battery separator from regenerated eggshell membrane with effective suppression of dendritic lithium growth

https://doi.org/10.1016/j.ensm.2018.04.016Get rights and content

Abstract

Lithium metal-based batteries are attractive energy storage systems owing to the high theoretical capacity of lithium metal anode and the known lowest potential among existing anodes. However, lithium anodes usually suffer from severe growth of lithium dendrites, a main reason of safety concern. Engineering the structure of separators could be an effective solution for resolving this issue. Herein, we demonstrate that eggshell membrane (ESM) extracted from waste eggshell is a promising candidate as high-performance separator. Furthermore, we have developed a biomimetic and economic strategy to produce large-area and flat regenerated ESM (RESM) to overcome the size and shape limits of raw ESM. The ESM and RESM are highly lyophilic to electrolytes; their well-distributed pores and high electrolyte uptake allow fast ion-diffusion; and their high mechanical and thermal stability ensure the safety and cyclability of batteries. Most impressively, the nanoporous structure and the negatively-charged surface of ESM and RESM separators can effectively suppress the formation of lithium dendrites, even after long-term cycling under high rate. Lithium-ion batteries, lithium-sulfur batteries, and sodium-ion batteries using RESM separators all show boosted rate capability and cycling retention, outperforming commercial separators on almost all fronts. Even at a high temperature (120 °C), lithium-ion batteries with RESM separators can still operate normally. Our findings indicate the nanoporous RESM film can meet most if not all requirements of an ideal separator for metal ion batteries.

Introduction

Since the application of batteries has been vigorously expanded into new fields, such as smart electronics, clean-energy vehicles and grid-scale storage, the search for portable, high capacity and safe electrical energy storage technologies has become one of the paramount motivators for battery material research [1], [2], [3], [4]. Lithium metal-based secondary batteries, including lithium–air, lithium–metal oxides and lithium–sulfur batteries (LSBs), are attractive alternatives to conventional lithium-ion batteries (LIBs), owning to the high theoretical capacity of lithium metal anode (3860 mA h g-1) and the lowest redox potential among all existing anodes [5], [6]. However, for the practical use of lithium metal anode, the severe dendritic lithium formation on the lithium metal surface should be suppressed [7], [8]. During the repeated charge-discharge cycling, the continuous uneven deposition and stripping of lithium induce uncontrollable growth of lithium dendrites, which can penetrate through the polymer separator and form micro-short circuits between the positive and negative electrodes, causing the serious safety issues including fire and even explosions [9], [10], [11], [12].

In recent years, although great efforts have been made on the optimization of electrolytes [13], [14], [15], [16], the achievements on suppressing dendritic lithium growth are still limited, because normally lithium metal cannot conformally contact the separator in microscale during charge/discharge processes. Separators with well-designed nanostructures hold the key for suppressing the growth of lithium dendrites. Traditionally, this problem was clumsily alleviated by using thicker and more tortuous separators. However, such separators normally lead to increased impedance loss, and still cannot fully suppress the dendritic lithium growth [17]. Currently, the most widely-used commercial separators (such as CelgardTM-2400 shown in Fig. S1) are made of polyolefin films [18], [19], [20], predominantly polyethylene (PE) or polypropylene (PP). Unfortunately, owning to the unsuitable morphology and pore size distribution of commercial separators, the capability for suppressing the formation and growth of lithium dendrites is very limited. Moreover, polyolefin films usually suffer from insufficient electrolyte wettability, low porosity and serious thermal shrinkage [21], [22], [23], [24], [25], which are partially responsible for the relatively poor electrochemical performance and poor safety of lithium metal-based batteries. Previous reports have explored the modification of commercial Celgard separator by coating with ceramic or polymer for improving the electrolyte affinity and resistance to thermal shrinkage [26], [27], [28]. It is ideal to design and fabricate novel separators that can solve all of the above issues.

Based on the systematic evaluation in lithium metal-based batteries, here we report that the pristine eggshell membrane (ESM) extracted from waste eggshell is a promising candidate of separator with remarkable properties. Moreover, to overcome the curved shape and limited size of raw ESM, we further develop a biomimetic and economic strategy to fabricate large-area and flat nanoporous regenerated ESM (RESM) film from pristine ESM. Interestingly, the nanoporous RESM film can well inherit and even significantly enhance the merits of raw ESM as battery separator. It should be noted that although ESM film was investigated for using in energy related applications, such as supercapacitor, synthesis template or starting material [29], [30], [31], [32], [33], [34], [35], [36], [37], but the detailed intrinsic properties, regeneration strategy and effects of ESM film for metal lithium-based secondary batteries still have not been investigated. With the good electrolyte wettability, high electrolyte uptake, good mechanical strength, high thermal stability and well-distributed porous structure of RESM film, the batteries with RESM film can exhibit greatly enhanced performances than those with commercial Celgard separator in terms of battery safety, reversible capacity, rate capability and long-term cycling stability under high rates. Impressively, the three-dimensional nanoporous and flexible RESM film can effectively suppress the dendritic lithium growth during charge/discharge processes and maintain a uniform ionic flux on the lithium metal surface.

Section snippets

Chemicals

The waste eggshells were collected from the canteen of Nanjing University. All other chemicals were purchased from Sinopharm Chemical Reagent Co., Ltd, and were of analytical grade and used without further purification.

Extraction of egg-shell membranes (ESM)

The waste eggshells were firstly cleaned with deionized water and then immersed into HCl solution (1.0 M) for 6 h to remove the hard CaCO3 outer shells. Then, the resultant ESM were washed with deionized water and dried at room temperature for 12 h.

Dissolution of ESM

The obtained ESM were cut into

Results and discussion

Fig. 1a shows the typical structure of bird or reptile eggs, which usually possess three protective layers: the hard eggshell, the outer ESM and the inner ESM. The hard eggshell is mainly composed of CaCO3 crystals stabilized by protein matrix, while the outer and inner ESM are primarily composed of a porous matrix of interwoven protein fibers and polysaccharides (glycans) [38], [39]. After the evolution by the Mother Nature for billions of years, ESM has developed numerous functions and merits

Conclusions

In summary, we show that the ESM and RESM acquired from abundant and renewable poultry sources can be used as close-to-ideal battery separators that fully outperforming the existing mainstream option. A key finding is the suppression of dendritic lithium growth when using lithium metal electrodes, solving a long standing problem in lithium metal based batteries. Finally, an effective method with high compatibility to current technologies was developed to prepare large-area and flat RESM from

Acknowledgements

This work is supported by National Key R&D Program of China (2017YFA0208200, 2016YFB0700600 and 2015CB659300), Projects of NSFC (21403105 and 21573108), Natural Science Foundation of Jiangsu Province (BK20150583 and BK20160647) and the Fundamental Research Funds for the Central Universities (020514380107).

References (56)

  • D.H. Wang et al.

    Traits of eggshells and shell membranes of translucent eggs

    Poult. Sci.

    (2017)
  • M. Xiong et al.

    Expanded polytetrafluoroethylene reinforced polyvinylidenefluoride–hexafluoropropylene separator with high thermal stability for lithium-ion Batteries

    J. Power Sources

    (2013)
  • N. Wu et al.

    Study of a novel porous gel polymer electrolyte based on TPU/PVdF by electrospinning technique

    Solid State Ion.

    (2011)
  • Y. Xie et al.

    Enhancement on the wettability of lithium battery separator toward nonaqueous electrolytes

    J. Membr. Sci.

    (2016)
  • S.S. Zhang

    A review on electrolyte additives for lithium–ion batteries

    J. Power Sources

    (2006)
  • R. Prasanth et al.

    Novel polymer electrolyte based on cob-web electrospun multicomponent polymer blend of polyacrylonitrile/poly(methyl methacrylate)/polystyrene for lithium ion batteries–preparation and electrochemical characterization

    J. Power Sources

    (2012)
  • W. Jiang et al.

    A high temperature operating nanofibrous polyimide separator in Li–ion battery

    Solid State Ion.

    (2013)
  • J.B. Goodenough et al.

    The Li–ion rechargeable battery: a perspective

    J. Am. Chem. Soc.

    (2013)
  • C.K. Chen et al.

    High–performance lithium battery anodes using silicon nanowires

    Nat. Nanotechnol.

    (2008)
  • S.S. Zhang

    A review on the separators of liquid electrolyte Li–ion batteries

    Science

    (2011)
  • D. Bruce et al.

    Electrical energy storage for the grid: a battery of choices

    Nature

    (2001)
  • J.M. Tarascon et al.

    Issues and challenges facing rechargeable lithium batteries

    Nature

    (2001)
  • K. Liu et al.

    Lithium metal anodes with an adaptive “solid-liquid” interfacial protective layer

    J. Am. Chem. Soc.

    (2017)
  • M. Armand et al.

    Building better batteries

    Nature

    (2008)
  • H. Kim et al.

    Metallic anodes for next generation secondary batteries

    Chem. Soc. Rev.

    (2013)
  • L. Fan et al.

    Recent progress of the solid-state electrolyte for high-energy metal-based batteries

    Adv. Energy Mater.

    (2018)
  • L. Fan et al.

    Stable lithium electrodeposition at ultra-high current densities enabled by 3D PMF/Li composite anode

    Adv. Energy Mater.

    (2018)
  • Y.Y. Lu et al.

    Stable lithium electrodeposition in liquid and nanoporous solid electrolyte

    Nat. Mater.

    (2014)
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