Lithium substituted poly(amic acid) as a water-soluble anode binder for high-temperature pre-lithiation

Abstract

Multifunctional binders hold great promise in advanced electrode designs for both fundamental research and practical utilization of lithium-ion batteries (LIBs). The reactions between Si/SiO x -dominated anodes with lithium are expected to be exothermic in principle, while the thermal tolerance along with the volume change makes high-temperature binders attractive for large scale roll-to-roll manufacturing. For instance, if a high temperature binder is also water soluble, it can be compatible with the current graphite-based anode manufacturing process. In this work, we present a water-soluble poly(amic acid)-based binder, which can withstand high temperature for industrial pre-lithiation process and effectively hold active materials together during repeated charge and discharge cycles. This lithium substituted poly(amic acid) binder (denoted as Li-Pa) can serve as a drop-in replacement for environmentally friendly electrode fabrication in large scale by providing aqueous solubility, exceptional thermal stability and mechanical flexibility. • A water-soluble lithium substituted poly(amic acid) binder was designed for Si electrodes. • Thermal imidization of lithium substituted poly(amic acid) to polyimide was achieved. • Polyimide binder based Si electrodes are thermally stable up to 500 °C. • High temperature pre-lithiation can be performed on these electrodes.