Carbon Nanotubes Supercharge Organic Battery Cathodes

As the world seeks greener energy solutions, researchers are looking beyond conventional metal oxide cathodes for lithium-ion batteries. Organic polymers have emerged as a promising alternative due to their safety and the abundance of their constituent elements. However, creating an organic cathode that balances high energy capacity with a long life cycle has proven to be a difficult engineering challenge.

In a recent breakthrough, scientists synthesised a new redox-active polyimide using active site-rich mellitic trianhydride (MTA) and naphthalene diimide (NDI). On its own, this pristine polymer demonstrated incredible durability, surviving over 20,000 charge cycles. However, its specific capacity—the amount of charge it can hold per unit of mass—remained relatively low at 60 mAh g^-1.

To overcome this limitation, the team engineered a hybrid material by integrating multi-walled carbon nanotubes (MWCNTs). This process of hybridisation transformed the material's performance. By adding just 10% carbon nanotubes by weight, the specific capacity nearly tripled to 170 mAh g^-1. This composite material, referred to as MTA-NDI@CNT, maintained stable performance over 1,300 cycles with over 60% capacity retention. This study suggests that combining engineered organic structures with conductive carbon networks could be key to developing sustainable, high-performance batteries.