Structure-Engineered Low-Cost Carbon Microbelt Hosts for Highly Robust Potassium Metal Anode

摘要

Potassium metal as anode is an ideal material for the assembly of high specificenergy batteries. However, safety issues caused by unrestricted dendritegrowth and “dead K” generation severely limit their application. Here, basedon the concept of waste recycling, a structural engineering strategy (chemicalexfoliation and enzyme-assisted synergistic method) is proposed to prepareoxygen-containing functionalized porous carbon microbelts (OPCMs) asfreestanding K metal hosts. The porous structure, uniformly distribution ofcarbon nanospheres, and the presence of oxygen-containing functionalgroups reduce the energy barrier of K nucleation and promote the depositionkinetics. Benefitting from these advantages of OPCMs, the OPCMs-based Kcomposite anodes (K-OPCMs) are free of obvious dendrite growth duringthe plating process. Symmetric cells assembled with K-OPCMs maintain astable overpotential of 40 mV after cycling for more than 800 h at 1 mA cm~(?2).In addition, the K-OPCMs//organic cathode (PTCDA) full cell exhibitsexcellent rate capability (96 capacity retention, 100–2000 mA g~(?1), which issuperior to most reported potassium metal batteries) and ultralong lifespan(97.8 mA h g~(?1), after 1500 cycles at 2000 mA g~(?1)). This study illustrates theeffectiveness of structure-engineered and provides a guiding insight forachieving high-performance rechargeable batteries.