Fast ion conductor

Electrode

Organic chemistry

Lithium battery

Endocrinology

Ionic conductivity

Engineering

Conductivity

Physical chemistry

Composite material

Ionic bonding

Chemistry

Materials science

Lithium (medication)

Polymerization

Electrolyte

Chemical engineering

Polymer

Electrochemistry

Medicine

Nature Energy

Solid-state electrolytes with high room-temperature ionic conductivity and fast interfacial charge transport are a requirement for practical solid-state batteries. Here, we report that cationic aluminium species initiate ring-opening polymerization of molecular ethers inside an electrochemical cell to produce solid-state polymer electrolytes (SPEs), which retain conformal interfacial contact with all cell components. SPEs exhibit high ionic conductivity at room temperature (&gt;1 mS cm−1), low interfacial resistances, uniform lithium deposition and high Li plating/striping efficiencies (&gt;98% after 300 charge–discharge cycles). Applications of SPEs in Li–S, Li–LiFePO4 and Li–LiNi0.6Mn0.2Co0.2O2 batteries further demonstrate that high Coulombic efficiency (&gt;99%) and long life (&gt;700 cycles) can be achieved with an in situ SPE design. Our study therefore provides a promising direction for creating solid electrolytes that meet both the bulk and interfacial conductivity requirements for practical solid polymer batteries. High-performance polymer electrolytes are highly sought after in the development of solid-state batteries. Lynden Archer and co-workers report an in situ polymerization of liquid electrolytes in a lithium battery for creating promising polymer electrolytes with high ionic conductivity and low interfacial resistance.

Solid-state polymer electrolytes with in-built fast interfacial transport for secondary lithium batteries