Bimetallic　phosphate　electrocatalysts　on　carbon-cloth　support　are　among　the　most　promising　industry-relevant　solutions　for　electrocatalytic　hydrogen　production.　To　address　the　persistent　issue　of　hetero-phase　interfacing　on　carbon　support　while　ensuring　high　activity　and　stability,　a　low-cost,　high-performance　hydrogen　evolution　reaction　(HER)　electrocatalyst　is　developed.　Bi-phase　Ni12P5-Ni(4)Nb(5)P(4)nanocrystals　with　rich　heterointerfaces　and　phase　edges　are　successfully　fabricated　on　carbon　cloth　(CC),　which　is　enabled　by　intentional　defect　creation　by　atmospheric　pressure　dielectric　barrier　discharge　(DBD)　plasma　(PCC).　The　obtained　Ni12P5-Ni4Nb5P4/PCC　electrocatalyst　exhibits　excellent　HER　performance,　heralded　by　the　low　overpotentials　of　81　and　287　mV　for　delivering　current　densities　of　10　(j(10))　and　500　(j(500))　mA　cm(-2),　respectively.　Meanwhile,　the　Ni12P5-Ni4Nb5P4/PCC　maintains　spectacular　catalytic　activity　at　high　current　density　region　(＞j(615)),　which　outperformed　the　industry-relevant　benchmark　Pt/C/PCC　catalyst.　The　catalyst　grown　on　the　plasma-treated　support　shows　remarkably　longer　operation　and　ultra-stable　electrocatalytic　characteristics　over　100　h　continuous　operation.　Ab　initio　numerical　simulations　reveal　that　Ni　atoms　exposed　in　the　heterointerfaces　act　as　the　main　catalytically　active　centers　for　HER.