During　the　operation　of　alkaline　fuel　cells　(AFCs),　a　significant　amount　of　waste　heat　is　generated,　which　has　negative　impacts　on　energy　utilization　and　the　environment.　To　improve　energy　efficiency,　cost　savings,　environmental　sustainability,　and　industrial　practices,　an　effective　approach　is　proposed　to　employ　thermogalvanic　cells　(TGCs)　for　electric　power　generation　by　harvesting　low-grade　exhaust　heat　produced　in　AFCs.　A　mathematical　model　of　the　AFC-TGC　hybrid　system　is　established,　taking　into　account　the　three　overpotential　losses　in　AFCs　and　the　irreversible　heat　losses　in　TGCs.　Based　on　this　thermal　-electric　coupled　model,　we　investigate　the　hybrid　system＇s　output　performance　characteristics　and　optimal　parameter　design.　The　calculated　results　indicate　that　the　hybrid　system　achieves　a　considerable　increase　of　19.72%　in　maximum　power　density　from　247.07　W　m-2　to　295.80　W　m-2　and　5.71%　in　conversion　efficiency　from　10.16%　to　10.74%　compared　to　a　single　AFC,　respectively.　In　addition,　the　output　performance　of　the　hybrid　system　can　be　further　improved　by　adjusting　system　parameters　such　as　the　AFC＇s　operating　temperature,　the　length　of　each　TGC　cell,　the　heat　sink　temperature,　and　the　thermal　convection　coefficient.　More　importantly,　a　comparative　study　of　the　maximum　power　density　of　AFC　-based　cogeneration　systems　reveals　that　the　TGC　demonstrates　a　remarkable　ability　to　economically　recover　waste　heat　from　the　AFC,　surpassing　previously　reported　thermal　energy　utilization　devices.　This　study　provides　important　theoretical　guidance　for　the　optimal　design　and　parametric　analysis　of　AFC-TGC　hybrid　systems,　thereby　facilitating　the　development　of　high-performance　energy　cascade　utilization　systems　based　on　AFC　devices.