Reversible and homogenous zinc deposition enabled by in-situ grown Cu particles on expanded graphite for dendrite-free and flexible zinc metal anodes

The rapid development of wearable electronics has boosted the exploration of flexible and safe energy storage devices, such as zinc ion batteries or capacitors; and suppressing the dendrite growth for Zn anode is essential for enhancing their performance. Addressing this, we report a dendrite-free and flexible Zn metal anode (Zn@Cu-Ps/ EG) that is based on expanded graphite (EG) decorated with in-situ formed copper particles (Cu-Ps). In this material, the Cu-Ps act as zincophilic seeds that reduce zinc nucleation overpotential, while the EG substrate induces epitaxial electrodeposition of zinc for suppressing dendrite growth. Moreover, the Cu-Ps nail the graphite nanosheets tightly and enhance the mechanical strength and flexibility of the Cu-Ps/EG composite. Consequently, the Zn@Cu-Ps/EG anode exhibits a low Zn deposition overpotential of 142.8 mV and superior cycling performance over 3000 h upon cycling at 10.0 mA cm-2 and 10.0 mAh cm-2. A flexible Zn-ion capacitor equipped with this anode delivers excellent cycling performance for over 1600 cycles at 1.0 A g-1 and stable power output at various bending statuses. This work provides a new approach for designing advanced flexible and dendrite-free Zn metal anodes for energy storage applications.