Cationic　group　distribution　and　elemental　composition　are　two　key　factors　determining　the　conductivity　and　stability　of　anion　exchange　membranes　(AEMs)　for　vanadium　redox　flow　batteries　(VRFBs).　Herein,　fluorinated　tetra-dimethylaminomethyl-poly(fluorenyl　ether)s　(TAPFE)s　were　designed　as　the　polymer　precursors,　which　were　reacted　with　6-bromo-N,N,N-trimethylhexan-1-aminium　bromide　to　introduce　di-quaternary　ammonium　(DQA)　containing　side　chains.　The　resultant　DQA-TAPFEs　with　a　rigid　fluorinated　backbone　and　flexible　multi-cationic　side　chains　exhibited　distinct　micro-phase　separation　as　probed　by　small-angle　X-ray　scattering　(SAXS)　and　atomic　force　microscopy　(AFM).　DQA-TAPFE-20　with　an　ion　exchange　capacity　(IEC)　of　1.55　mmol　g-1　exhibited　a　SO42-　conductivity　of　10.1　mS　cm-1　at　room　temperature,　much　higher　than　that　of　a　control　AEM　with　an　identical　backbone　but　spaced　out　cationic　groups,　which　had　a　similar　IEC　of　1.60　mmol　g-1　but　a　SO42-　conductivity　of　only　3.2　mS　cm-1.　Due　to　the　Donnan　repulsion　effect,　the　DQA-TAPFEs　exhibited　significantly　lower　VO2+　permeability　than　Nafion　212.　The　VRFB　assembled　with　DQA-TAPFE-20　achieved　an　energy　efficiency　of　80.4%　at　80　mA　cm-1　and　a　capacity　retention　rate　of　82.9%　after　the　50th　cycling　test,　both　higher　than　those　of　the　VRFB　assembled　with　Nafion　212　and　other　AEMs　in　the　literature.　Therefore,　the　rationally　designed　DQA-TAPFEs　are　promising　candidates　for　VRFB　applications.　©