The　rise　of　portable　and　wearable　electronics　has　largely　stimulated　the　development　of　flexible　energy　storage　and　conversion　devices.　As　one　of　the　essential　parts,　the　electrode　plays　critical　role　in　determining　the　device　performance,　which　required　to　be　highly　flexible,　light-weight,　and　conformable　for　flexible　and　wearable　applications.　However,　it　remains　a　formidable　challenge　in　the　design　of　appropriate　flexible　electrodes.　Thus,　considerable　effort　has　been　making　to　develop　various　flexible　materials/substrates　to　fabricate　flexible　energy　devices.　Here,　this　review　aims　to　provide　a　comprehensive　survey　on　the　recently　developed　free-standing　and　flexible　electrode　materials/substrates　for　flexible　electrochemical　energy　storage　devices,　which　are　categorized　into　four　different　types　including　metal-based,　carbon-based,　polymer-based,　and　micro-patterned　flexible　electrodes.　The　specific　characteristics,　fabrication　methods,　properties,　and　pros　and　cons　of　each　type　of　materials　are　thoroughly　analysed.　Furthermore,　challenges　and　future　directions　for　designing　flexible　electrode　materials　are　also　discussed.