Electrospinning preparation of Sb₂Se₃/TiO₂/C nanofiber anode and its application in lithium-ion batteries

In the current era of rapid scientific and technological development, flexible electronics and wearable devices have emerged as a trend, leading the way in fashion. These devices require flexible batteries to power them. The mechanical flexibility of electrodes is crucial in determining whether flexible batteries can withstand repeated folding or bending. Electrospinning is a simple and effective method for preparing flexible electrodes for lithium-ion batteries. In this context, a flexible Sb₂Se₃/TiO₂/C nanofiber membrane was synthesized using electrospinning technology, with titanium isopropoxide (TTIP) serving as a coupling agent to enhance its mechanical flexibility. The synthesized flexible Sb₂Se₃/TiO₂/C nanofiber membrane can withstand 180° bending and folding; it has been folded 50 times at 180° without any signs of breakage. To assess the electrochemical performance of the flexible Sb₂Se₃/TiO₂/C nanofiber, we employed it as a freestanding anode. The electrochemical performance of the Sb₂Se₃/TiO₂/C nanofiber membrane anode was thoroughly investigated in both Li half-cells and Li full-cells. Performance testing of the half-cell demonstrated the superior rate capability and cycling performance of the Sb₂Se₃/TiO₂/C nanofiber membrane. At a current density of 50 mA·g⁻¹, the membrane achieved an initial reversible capacity of 470.1 mA·h·g⁻¹, with a capacity retention rate of 86.1% after 100 cycles. The electrochemical performance of the Sb₂Se₃/TiO₂/C nanofiber membrane far surpassed that of the commercial bulk Sb₂Se₃ anode. Rate capabilities were investigated at current densities of 50, 100, 200, 400, 600, 800, and 1000 mA·g⁻¹, within a test voltage range from 0.01 to 2.5 V. Cycling performance testing was conducted at 50 mA·g⁻¹ with a test potential range of 0.01–2.5 V. The high Li⁺ transport capability of the Sb₂Se₃/TiO₂/C nanofiber membrane contributed to its excellent electrochemical performance. Additionally, the electrochemical performance of a full battery assembled with a freestanding Sb₂Se₃/TiO₂/C nanofiber anode and LiNi_0.88Co_0.06Mn_0.06O₂ cathode was tested at a current density of 50 mA·g⁻¹, with a voltage range of 1.0–4.3 V. Full cell tests confirmed the excellent electrochemical properties of the flexible Sb₂Se₃/TiO₂/C nanofiber membrane, demonstrating its potential for practical applications. The combination of its impressive mechanical flexibility and unique nanofiber conductive network contributed significantly to its outstanding electrochemical performance. Through various experimental characterizations, we demonstrated that the robust mechanical flexibility and distinctive nanofiber conductive network of the flexible Sb₂Se₃/TiO₂/C nanofiber membrane collectively enhanced its electrochemical capabilities.