Concomitant Mitigation of VO 6 Octahedron Distortion and Band Broadening in V 2 O 3 for High‐Performing Flexible Supercapacitors

Abstract Vanadium trioxide (V 2 O 3 ) has emerged as one of the promising candidates for fiber‐shaped supercapacitors. However, irreversible redox behavior during prolonged cycling process has been commonly reported due to the intrinsically distorted VO 6 octahedron in V 2 O 3 , which inevitably compromises its electrochemical capacitance. Herein, a strategy to simultaneously mitigate the distortion in VO 6 octahedron and optimization of electronic structure in V 2 O 3 is proposed by studying a Mo‐doped V 2 O 3 modified stainless steel wire (Mo‐V 2 O 3 @SSW). The introduction of Mo dopants effectively tunes the V–O local environment, resulting in a substantial alleviation of the distortion in VO 6 octahedron. The as‐prepared Mo‐V 2 O 3 with a more regular VO 6 octahedron exhibits highly reversible redox behavior, with negligible structural change after 10 000 cycles. Moreover, it is found that doping Mo into V 2 O 3 leads to V 3d band broadening, which generates more electronic states around Fermi level, thereby significantly accelerating the electron transfer during redox processes. Consequently, Mo‐V 2 O 3 @SSW attains a capacitance of 774.4 mF cm −2 at 0.4 mA cm −2 , with a capacitance retention of 85.49% after 10 000 cycles. And the integration of Mo‐V 2 O 3 @SSW supercapacitors, further showcases its strong applicability in wearable technologies. The comprehensive understanding of the structural–activity/stability relationship in this study offers a novel paradigm for developing flexible high‐performing supercapacitors.