Similar　to　MXene,　MAB　is　a　group　of　2D　ceramic/metallic　boride　materials　which　exhibits　unique　properties　for　various　applications.　However,　these　2D　sheets　tend　to　stack　and　therefore　lose　their　active　surface　area　and　functions.　Herein,　an　amorphous　cobalt　nickel　boride　(Co-Ni-B)　nanocomposite　is　prepared　with　a　combination　of　2D　sheets　and　nano　particles　in　the　center　to　avoid　agglomeration.　This　unique　structure　holds　the　2D　nano　sheets　with　massive　surface　area　which　contains　numerous　catalytic　active　sites.　This　nanocomposite　is　prepared　as　an　electrocatalyst　for　borohydride　electrooxidation　reaction　(BOR).　It　shows　outstanding　catalytic　activity　through　improving　the　kinetic　parameters　of　BH4-　oxidation,　owing　to　abundant　ultrathin　2D　structure　on　the　surface,　which　provide　free　interspace　and　electroactive　sites　for　charge/mass　transport.　The　anode　catalyst　led　to　a　209　mW/cm(2)　maximum　power　density　with　high　open　circuit　potential　of　1.06　Vat　room　temperature　in　a　miniature　direct　borohydride　fuel　cell　(DBFC).　It　also　showed　a　great　longevity　of　up　to　45　h　at　an　output　power　density　of　64　mW/cm(2),　which　is　higher　than　the　Co-B,　Ni-B　and　PtRu/C.　The　cost　reduction　and　prospective　scale-up　production　of　the　Co-Ni-B　catalyst　are　also　addressed.　(C)　2021　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.