CoFe₂O₄/carbon nanotube aerogels as high performance anodes for lithium ion batteries

High-performance lithium ion batteries (LIBs) require electrode material to have an ideal electrode construction which provides fast ion transport, short solid-state ion diffusion, large surface area, and high electric conductivity. Herein, highly porous three-dimensional (3D) aerogels composed of cobalt ferrite (CoFe₂O₄, CFO) nanoparticles (NPs) and carbon nanotubes (CNTs) are prepared using sustainable alginate as the precursor. The key feature of this work is that by using the characteristic egg-box structure of the alginate, metal cations such as Co²⁺ and Fe³⁺ can be easily chelated via an ion-exchange process, thus binary CFO are expected to be prepared. In the hybrid aerogels, CFO NPs interconnected by the CNTs are embedded in carbon aerogel matrix, forming the 3D network which can provide high surface area, buffer the volume expansion and offer efficient ion and electron transport pathways for achieving high performance LIBs. The as-prepared hybrid aerogels with the optimum CNT content (20 wt%) delivers excellent electrochemical properties, i.e., reversible capacity of 1033 mAh g⁻¹ at 0.1 A g⁻¹ and a high specific capacity of 874 mAh g⁻¹ after 160 cycles at 1 A g⁻¹. This work provides a facile and low cost route to fabricate high performance anodes for LIBs.