We report the successful fabrication of a micro-pseudocapacitor based on ternary nickel cobalt sulfide for the first time, with performance substantially exceeding that of previously reported micro-pseudocapacitors based on binary sulfides. The CoNi2S4 micro-pseudocapacitor exhibits a maximum energy density of 18.7 mW h cm(-3) at a power density of 1163 mW cm(-3), and opens up an avenue for exploring a new family of ternary oxide/sulfide based micro-pseudocapacitors.