Carbon nanotubes loaded with carbon nanofibers as scaffold for Li metal battery anodes

Lithium (Li) metal base battery is the most attractive anode for high energy density batteries since its high theoretical capacity and low anode potential. However, the irreversible Li plating/stripping can induce the decrease of cyclic capability and the growth of lithium dendrite, leading to a series of issues like infinite volume change, low coulombic efficiency, and short circuit. Herein, a 3D conductive carbon nanofibers scaffold with carbon nanotubes (CNTs/CNFs) obtained through a simple electrospinning method, which can be used to regulate metallic Li deposition and inhibit the growth of Li dendrites. On the other hand, CNTs/CNFs scaffold can prove ample space for lithium deposition and alleviate the huge volumetric variation during the discharge/charge cycles. Since the introduction of CNTs, the CNTs/CNFs electrode exhibits a highly reversible plating/stripping with an extremely low overpotential upon >500 h at 1 mA cm−2 in symmetric cells, respectively. Even the high current density up to 5 mA cm−2, the cell still shows a minimum overpotential of 92 mV upon >50 h. When the Li deposited CNTs/CNFs (Li@CNTs/CNFs) anode is applied in a full cell with a commercial LiFePO4 cathode, a stable capacity of 123 mAh g−1 can be still achieved 150 cycles. It is anticipated that the CNTs/CNFs scaffold could be further combined with electrolytes and cathodes to develop high-performance energy systems.