Robust potassium metal anodes realized by ferroelectricity and high conductivity separator

Low-cost potassium (K) metal batteries (KMBs) have drawn broad attention due to the prospect of wide applications. However, the applications of KMBs have been severely troubled by the problems from the K dendrites and dead K. The disordered K dendrite growth causes repeated fracture and repair of solid electrolyte interphase (SEI), and the aggregation of dead K detached from current collectors around the cathode region leads to rapid capacity attenuation in KMBs. Herein, a barium titanate/reduced graphene oxide (BaTiO3@rGO) composite on glass fiber (GF) separator was prepared with ferroelectrically spin-polarized and high conductive, which highly effective in inhibiting disorderly K dendrite growth and activate the inactive dead K by improving electrochemical performance without affecting the transport of positively charged K ions. The capacity retention ratio (CRR) and attenuation rate of full-cell of KMBs adopting BaTiO3@rGO separator are 87% and 0.02% after 380 cycles at 0.5A g−1, respectively. This research defines an effective strategy to inhibit K dendrites and activate dead K in KMBs.