Electrochemical　power　sources,　as　one　of　the　most　promising　energy　storage　and　conversion　technologies,　provide　great　opportunities　for　developing　high　energy　density　electrochemical　devices　and　portable　electronics.　However,　uncontrolled　ionic　transport　in　electrochemical　energy　conversion,　typically　undesired　anion　transfer,　usually　causes　some　issues　degrading　the　performance　of　energy　storage　devices.　Nanochannels　offer　an　effective　strategy　to　solve　the　ionic　transport　problems　for　boosting　electrochemical　energy　storage　and　conversion.　In　this　review,　the　advantages　of　nanochannels　for　electrochemical　energy　storage　and　conversion　and　the　construction　principle　of　nanochannels　are　introduced,　including　ion　selectivity　and　ultrafast　ion　transmission　of　nanochannels,　which　are　considered　as　two　critical　factors　to　achieve　highly　efficient　energy　conversion.　Recent　advances　in　applications　of　nanochannels　in　lithium　secondary　batteries　(LSBs),　electrokinetic　energy　conversion　systems　and　concentration　cells　are　summarized　in　detail.　Nanochannels　exist　in　the　above　systems　in　two　typical　forms:　functional　separator　and　electrode　protective　layer.　Current　research　on　nanochannel-based　LSBs　is　still　at　the　early　stage,　and　deeper　and　broader　applications　are　expected　in　the　future.　Finally,　the　remaining　challenges　of　nanochannel　fabrication,　performance　improvement,　and　intelligent　construction　are　presented.　It　is　envisioned　that　this　paper　will　provide　new　insights　for　developing　high-performance　and　versatile　energy　storage　electronics　based　on　nanochannels.