Bismuth　(Bi)　has　been　considered　as　a　promising　alloyingtype　anode　for　potassium-ion　batteries　(PIBs),　owing　to　its　high　theoretical　capacity　and　suitable　working　voltage　plateaus.　However,　Bi　suffers　from　dramatic　volume　fluctuation　and　significant　pulverization　during　the　discharge/charge　processes,　resulting　in　fast　capacity　decay.　Herein,　we　synthesize　Bi　nanoparticles　confined　in　carbonaceous　nanospheres　(denoted　as　Bi@C)　for　PIBs　by　first　utilizing　BiOCl　nanoflakes　as　a　hard　template　and　a　Bi　precursor.　The　construction　of　the　loose　structure　buffers　the　mechanical　stresses　resulting　from　the　volume　expansion　of　Bi　during　the　alloying　reaction　and　avoids　the　fracture　of　the　electrode　structure,　thus　improving　the　cycling　performance.　Moreover,　the　carbonaceous　layers　increase　the　electronic　conductivity　and　disperse　the　Bi　nanoparticles,　enhancing　the　charge　transportation　and　ionic　diffusion,　which　further　promotes　the　rate　capability　of　Bi@C.　It　exhibits　a　superior　capacity　(389　mAh　g(-1)　at　100　mA　g(-1)　after　100　cycles),　excellent　cycling　stability　(206　mAh　g(-1)　at　500　mA　g(-1)　over　1000　cycles),　and　an　improved　rate　capability　(182　mAh　g(-1)　at　2.0　A　g(-1)).　This　work　provides　a　new　structuring　strategy　in　alloying　materials　for　boosting　reversible　and　stable　potassium-ion　storage.