Ultrafast extreme thermal-electrical fabrication of volcano-shape-like core-shell Ag-MnxOy branches anchored on carbon as high-performance electrochemical electrodes

Abstract

Rationally designed hybrids of metal/metal oxides/carbon-based materials can overcome the fundamental limits of single-material electrodes. However, their conventional synthesis causes phase/interface segregation/unintended diffusive characteristics of building blocks. Herein, we report an ultrafast extreme thermal-electrical wave (UTEW) which is a Joule heating-driven, tunable and scalable synthesis technique for unusually arranged and morphologically trapped Ag-MnxOy-carbon fiber (CF) electrochemical electrodes. UTEW induces thermochemical reactions passing through entire precursor mixtures of silver-manganese nitrates and CF within a few seconds. The programmable temperature ranges and heating-cooling rates/duration enable morphological traps capturing metastable phases and wetted interfaces of the constituents, thereby fabricating unique volcano-shapelike core-shell Ag-MnxOy branches anchored on CF (VCS-Ag-MnxOy-CF). The comparison with other electrodes (Ag-CF and MnxOy-CF) elucidate the formation mechanism of VCS-Ag-MnxOy-CF and the synergistic effects of rationally combined Ag-MnxOy-CF in electrochemical performances. The UTEW fabrication strategy will inspire fascinating hybrid electrodes and catalysts which cannot be achieved through conventional fabrication methods.