Carbon‐Coated Electrospun V<sub>2</sub>O<sub>5</sub> Nanofibers as Photoresponsive Cathode for Lithium‐Ion Batteries
Michael Wilhelm, Ruth Adam, Aman Bhardwaj, Iuliia Neumann, Sunghun Cho, Yuki Yamada, Tohru Sekino, Jianming Tao, Zhensheng Hong, Thomas Fischer, Sanjay Mathur
Abstract
Photo‐rechargeable batteries represent a synergistic concept that integrates both energy harvesting and energy storage modalities based on dual‐functional materials. Electrospun vanadium oxide nanofibers (VNFs) seamlessly coated with conductive carbon (VNF‐C‐120) as dual‐action cathode materials for photo‐rechargeable lithium‐ion batteries (LIBs) are reported. The materials deliver a high discharge capacity of 160 mAh g −1 , which could be increased up to 184 mAh g −1 (C rate of 0.75) under light illumination that confirmed the photoresponsive behavior. Long‐term stability tests (300 cycles at 0.75C) and the post‐mortem analysis show that besides being a conductive sheath, the carbon coating is also essential in retaining the structural and morphological stability of V 2 O 5 fibers, which was manifested in a higher capacity retention upon cycling compared to the non‐carbon‐coated VNF (43.85% capacity retention VNF and 61.13% capacity retention for VNF‐C‐120 after 300 cycles). In contrast, the pristine VNF electrode cannot reach 400 cycles, due to the failure of the cell, which, however, is prevented in cells operating with carbon‐coated electrodes. Further, the photo‐rechargeability of the cell is demonstrated under a UV lamp that delivered an overall conversion efficiency of 4.24% for VNF and 5.07% for the VNF‐C‐120.