A Hollow‐Shell Structured V₂O₅ Electrode‐Based Symmetric Full Li‐Ion Battery with Highest Capacity

Abstract The symmetric batteries with an electrode material possessing dual cathodic and anodic properties are regarded as an ideal battery configuration because of their distinctive advantages over the asymmetric batteries in terms of fabrication process, cost, and safety concerns. However, the development of high‐performance symmetric batteries is highly challenging due to the limited availability of suitable symmetric electrode materials with such properties of highly reversible capacity. Herein, a triple‐hollow‐shell structured V₂O₅ (THS‐V₂O₅) symmetric electrode material with a reversible capacity of >400 mAh g⁻¹ between 1.5 and 4.0 V and >600 mAh g⁻¹ between 0.1 and 3.0 V, respectively, when used as the cathode and anode, is reported. The THS‐V₂O₅ electrodes assembled symmetric full lithium‐ion battery (LIB) exhibits a reversible capacity of ≈290 mAh g⁻¹ between 2 and 4.0 V, the best performed symmetric energy storage systems reported to date. The unique triple‐shell structured electrode makes the symmetric LIB possessing very high initial coulombic efficiency (94.2%), outstanding cycling stability (with 94% capacity retained after 1000 cycles), and excellent rate performance (over 140 mAh g⁻¹ at 1000 mA g⁻¹). The demonstrated approach in this work leaps forward the symmetric LIB performance and paves a way to develop high‐performance symmetric battery electrode materials.