The aim of this paper is to demonstrate lithium metal battery cells assembled with high potential cathodes produced by sustainable processes. Specifically, LiNi0.5Mn1.5O4 (LMNO) electrodes were fabricated using two different water-processable binders: pullulan (PU) or the bifunctional electronically conductive poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS). The cell performance was evaluated by voltammetric and galvanostatic charge/discharge cycles at different C-rates with 1M LiPF6 in 1:1 (v:v) ethylene carbonate (EC):dimethyl carbonate (DMC) (LP30) electrolyte and compared to that of cells assembled with LMNO featuring poly(vinylidene difluoride) (PVdF). At C/10, the specific capacity of LMNO-PEDOT:PSS and LMNO-PU were, respectively, 130 mAh g−1 and 127 mAh g−1, slightly higher than that of LMNO-PVdF (124 mAh g−1). While the capacity retention at higher C-rates and under repeated cycling of LMNO-PU and LMNO-PVdF electrodes was similar, LMNO-PEDOT:PSS featured superior performance. Indeed, lithium metal cells assembled with PEDOT:PSS featured a capacity retention of 100% over 200 cycles carried out at C/1 and with a high cut-off voltage of 5 V. Overall, this work demonstrates that both the water-processable binders are a valuable alternative to PVdF. In addition, the use of PEDOT:PSS significantly improves the cycle life of the cell, even when high-voltage cathodes are used, therefore demonstrating the feasibility of the production of a green lithium metal battery that can exhibit a specific energy of 400 Wh kg−1, evaluated at the electrode material level. Our work further demonstrates the importance of the use of functional binders in electrode manufacturing.
Semisolid redox flow
batteries simultaneously address the need
for high energy density and design flexibility. The electrical percolating
network and electrochemical stability of the flowable electrodes are
key features that are required to fully exploit the chemistry of the
semisolid slurries. Superconcentrated electrolytes are getting much
attention for their wide electrochemical stability window that can
be exploited to design high-voltage batteries. Here, we report on
the effect of the ion concentration of superconcentrated electrolytes
on the electronic percolating network of carbonaceous slurries. Slurries
based on different concentrations of lithium bis(trifluoromethane)sulfonamide
in tetraethylene glycol dimethyl ether (0.5, 3, and 5 mol/kg) at different
content of Pureblack carbon (from 2 up to 12 wt %) have been investigated.
The study was carried out by coupling electrochemical impedance spectroscopy
(EIS), optical fluorescence microscopy, and rheological measurements.
A model that describes the complexity and heterogeneity of the semisolid
fluids by multiple conductive branches is also proposed. For the first
time, to the best of our knowledge, we demonstrate that besides their
recognized high electrochemical stability, superconcentrated electrolytes
enable more stable and electronically conductive slurry. Indeed, the
high ionic strength of the superconcentrated solution shields interparticle
interactions and enables better carbon dispersion and connections.
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