Along　the　way　to　developing　highly　active　catalysts,　the　fabrication　of　unique　architectures　is　significant　in　determining　the　performance　of　energy　conversion　and　storage　devices.　One　of　the　highly　competitive　options　is　surface-modified　with　dispersed　nanoparticles　by　an　simply　in-situ　growth　strategy.　Typically,　the　exsolution　of　active　nanoparticles　is　demonstrated　in　the　irregular　powders　of　perovskite　oxides.　Here,　we　report　the　rational　design　and　fabrication　of　a　porous　A-site-deficient　titanate　fiber　decorated　by　exsolved　Ni　nanoparticles　as　a　highly　efficient　and　robust　fuel　electrode　for　solid　oxide　cells.　We　find　that　the　porosity　of　fiber　is　one　of　the　pronounced　effects　on　the　Ni　exsolution.　Based　on　the　finite　element　simulation　method　and　experiments,　it　is　demonstrated　that　the　addition　of　Gd0.1Ce0.9O2　(GDC)　in　fibrous　fuel　electrode　enhances　the　contact　and　connectivity　between　fibers.　This　unique　microstructure　not　only　provides　high　specific　surface　area　and　more　active　sites　but　also　benefits　to　easier　mass　transfer　and　charge　transfer,　resulting　in　a　much　lower　polarization　resistance.　The　corresponding　device　shows　superior　electrochemical　performance　and　durability　in　humified　H2　(3%　H2O).　This　highly　active　and　robust　fuel　electrode　together　with　the　unique　architectures　lays　a　strong　foundation　for　designing　high-electrochemical　active　devices.　©　2020　Elsevier　B.V.