MWCNT-embedded Li₄Ti₅O₁₂ microspheres interfacially modified with polyaniline as ternary composites for high-performance lithium ion battery anodes

In this study we used a spray-drying process and in situ polymerization to construct ternary composites of Li₄Ti₅O₁₂ (LTO) embedded with multi-walled carbon nanotubes (MWCNTs) and interfacially modified with polyaniline (PANI). In these composites, the introduced MWCNTs served as conductive backbones within the spray-dried LTO microspheres, thereby lowering the internal resistance of the microcomposites. The polymerized PANI acted as a conductive adhesive to strengthen the interactions between the MWCNTs and the LTO, leading to a sturdier interface and enhanced ionic transport properties. With the combined effects of the embedded MWCNTs and the interfacially polymerized PANI, we observed significant enhancements in both the conductivity and the ionic diffusion kinetics of the LTO composites. As a result, the ternary composites displayed outstanding electrochemical performance, including enhanced rate capability and remarkable cycling stability. The ternary system delivered a discharge capacitance (134.98 mA h/g) at 20 C that was higher than those of bare LTO (38.6 mA h/g) and MWCNT/LTO (114.88 mA h/g). Furthermore, the composites also exhibited 92.7% retention of their specific capacitance after 200 repeated charge/discharge tests, indicating their excellent cycling life.