Improved Electrochemical Performance of Lithium-Rich Manganese-Based Materials via a PI/MWCNT Composite Coating Layer

Lithium-rich manganese-based (LRM) materials have emerged as leading contenders for next-generation LIBs, delivering exceptional energy densities (>900 W h kg^-1), while maintaining cost advantages over cobalt-containing alternatives. However, the voltage decay, capacity loss, and life reduction have hindered their further commercialization. Herein, the strategy of using a polyimide/multi-walled carbon nanotubes (PI/MWCNTs) composite coating layer is proposed to optimize the microstructure and enhance the electrochemical properties. The novel PI is constructed with the highly polar and microbranched cross-linking network, which significantly enhances the interface structure stability. The MWCNTs in situ loaded on the LRM particles provide abundant electron transfer sites. Therefore, an initial discharge capacity of the coated-LRM is 238.7 mA h g^-1 between 2 and 4.6 V at 0.1C @ 25 °C, which is slightly higher than that of LRM (217.5 mA h g^-1). The coated LRM and LRM maintain 73% and 41% of their initial discharge capacities at 1C between 2 and 4.6 V after 200 cycles, respectively.