Performance Comparison of LMNO Cathodes Produced with Pullulan or PEDOT:PSS Water-Processable Binders

The aim of this paper is to demonstrate lithium metal battery cells assembled with high potential cathodes produced by sustainable processes. Specifically, LiNi 0.5 Mn 1.5 O 4 (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 LiPF 6 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.