In-situ polymerized and crosslinked electrolytes with interchangeable Li/Na transport for battery applications

The next generation of batteries requires electrolytes with high conductivity, mechanical stability, good adhesion with electrodes, wide electrochemical window, and scalability. The present study introduces a concept of doped quasi single-ion conducting copolymers based on methacrylate-TFSI and vinyl ethylene carbonate which at room temperature are mechanically robust and display ionic conductivities of ~0.1 mS/cm. These electrolytes can be polymerized/crosslinked in-situ, thus can be easily implemented in current battery manufacturing technologies, and allow to switch between Li⁺ and Na⁺ transport using simple chemistry procedures. To demonstrate their potential for battery applications, the newly developed Li conductor have been tested in symmetric cells, exhibiting overall impedance below 350  and plating/stripping stability up to 1 mA/cm2. Moreover, Li metal batteries incorporating this electrolyte and high voltage Lithium Nickel Manganese Cobalt Oxide (NMC) cathodes show good capacity retention (~79%) during charging and discharging for 80 cycles at C/10 rate and a Coulombic efficiency close to 100% in the entire measurement range. The compositional, mechanical and electrochemical versatility of these electrolytes opens new venues for the design of polymer-based batteries capable of fast charging extended cycle life, aligning with the current global green energy storage strategies.