Deciphering the Interplay between Binders and Electrolytes on the Performance of Li4Ti5O12 Electrodes for Li-Ion Batteries

Abstract

Lithium titanium oxide (Li4Ti5O12, LTO) is an attractive negative electrode for the development of safe—next-generation—lithium-ion batteries (LIBs). LTO can find specific applications complementary to existing alternatives for LIBs thanks to its good rate capability at high C-rates, fast lithium intercalation, and high cycling stability. Furthermore, LIBs featuring LTO electrodes are inherently safer owing to the LTO’s operating potential of 1.55 V vs. Li+/Li where the commonly used organic-based electrolytes are thermodynamically stable. Herein, we report the combined use of water-soluble sodium alginate (SA) binder and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-tetraglyme (1m-T) electrolyte and we demonstrate the improvement of the electrochemical performance of LTO-based electrodes with respect to those operating in conventional electrolyte 1M LiPF6-ethylene carbonate: dimethyl carbonate (LP30). We also tackle the analysis of the impact of combining the binder/electrolyte on the long-term cycling performance of LTO electrodes featuring SA or conventional polyvinylidene fluoride (PVdF) as binders. Therefore, to assess the impact of the combination of binder/electrolyte on performance, we performed post-mortem characterization by ex situ synchrotron diffraction experiments of LTO electrodes after cycling in LP30 and 1m-T electrolytes.

The ENEA′s 2019–2021 Three‐Year Research Project on Electrochemical Energy Storage

“…[35] It was also demonstrated the feasibility of a chitosan-based binder to produce freestanding electrodes for Na ion cells, without the use of organic solvents and current collectors in electrode processing [36] and sodium alginate as binder for lithium titanate-based electrodes. [37] Semisolid redox flow batteries simultaneously address the need for high energy density and design flexibility. For this kind of batteries, high electrical percolating network and elevated electrochemical stability of the flowable electrodes are required.…”

“…Furthermore, components of vegetable origin were tested as a binder [31–37] for both LIBs and SIBs. The use of pullulan as a binder was first demonstrated in a supercapacitor with carbon electrodes obtained from pepper‐seeds waste [31,32] and then in a lithium metal battery using a LNMO‐based cathode [33] .…”

“…When used as the anode of a LIB cell, the irradiated material showed a high specific capacity (1108, 682 and 578 mAhg À 1 at cycles 1, 10 and 20, respectively), good capacity retention (52 % at cycle 20 in respect to cycle 1), and relatively high first cycle Coulombic efficiency (56 %). [30] Furthermore, components of vegetable origin were tested as a binder [31][32][33][34][35][36][37] for both LIBs and SIBs. The use of pullulan as a binder was first demonstrated in a supercapacitor with carbon electrodes obtained from pepper-seeds waste [31,32] and then in a lithium metal battery using a LNMO-based cathode.…”