Alternatives to fluorinated binders: recyclable copolyester/carbonate electrolytes for high-capacity solid composite cathodes

Abstract

A series of poly(ester-b-carbonate) electrolytes are prepared by a one-pot procedure and structure–property relationships are observed. The polymer was used as a composite cathode binder with excellent discharge capacity and capacity retention.

Polymer design for solid-state batteries and wearable electronics

“…Polyester: random enchainment of 80 : 20 mol% CL : TMC is optimal and block copolymers have been explored with this mainly polyester SPE. 72,74 Block copolymers: di-and tri-blocks reported at various compositions of PS and PEO; PC- b -PEO- b -PC is discussed later as a composite cathode binder. Single Li-ion conductors (SLIC): Li aluminate dynamic crosslinked networks with fluorinated diol, FTEG (=1 H ,1 H ,11 H ,11 H -perfluoro-3,6,9-trioxaundecane-1,11-diol) and Li borate networks with poly(5-methyl-5-allyloxycarbonyl-trimethylene carbonate), PMAC.…”

“…For example, the ROP of trimethylene carbonate (TMC) and ε-caprolactone (CL) monomers can proceed to CO 2 /epoxide ROCOP when CO 2 is introduced to yield PC- b -P(TMC- co -CL)- b -PC without the need for intermediate purification steps. 72 This is also possible because the same catalyst can conduct both ROP and ROCOP mechanisms. 73 Another approach is the use of a difunctional ATRP agent where a hydroxyl group functionality was used to initiate TMC/CL ROP to form the ion-conducting segment, and then ATRP was conducted to form a poly(benzyl methacrylate) mechanical modifier block.…”

“…6a ). 72 As proof of principle over the lack of end-of-life options for fluorinated binders, the polymer was subsequently extracted from the cell and depolymerised to recover 90% of the starting monomers. Here, the comparison was made with PTFE rather than PVDF, the former being common for dry-processing composite cathodes as it is thought to form extended nano-fibril networks that are beneficial to electrode integrity.…”

Polyester‐Polycarbonate Polymer Electrolytes Beyond LiFePO4: Influence of Lithium Salt and Applied Potential Range

“…Recently, the PCL-PTMC copolymer has also been used as a promising alternative to fluorinated binders in composite electrodes, further pointing at the versatility of this material as well as the importance of moving away from fluorinated compounds. [16] And although this polymer material shows high oxidative stability, further insight is needed on how to better cycle this material in high operating voltage cells.…”

Lithium Borate Polycarbonates for High‐Capacity Solid‐State Composite Cathodes

“…Similarly, we also demonstrated poly(ester-block-carbonate)/LiFSI mixtures as recyclable non-fluorinated binders in analogous composites with SC-NMC811. [18] Both are examples of dualion conducting polymers, i.e., where both the anion and cation are able to move. Conversely, single-ion conducting polymers have anionic backbones and only allow for the Licounterion to be mobile.…”