Nitrile Electrolyte Strategy for 4.9 V-Class Lithium-Metal Batteries Operating in Flame

Challenges facing high-voltage/high-capacity cathodes,in addition to the longstanding problems pertinent to lithium(Li)-metal anodes,should be addressed to develop high-energy-density Li-metal batteries.This issue mostly stems from interfacial instability between electrodes and electrolytes.Conventional carbonate-or ether-based liquid electrolytes suffer from not only volatility and flammability but also limited electrochemical stability window.Here,we report a nitrile electrolyte strategy based on concentrated nitrile electrolytes(CNEs)with co-additives.The CNE consists of high-concentration lithium bis(fluorosulfonyl)imide(LiFSI)in a solvent mixture of succinonitrile(SN)/acetonitrile(AN).The SN/AN solvent mixture is designed to ensure high oxidation stability along with thermal stability,which are prerequisites for high-voltage Li-metal cells.The CNE exhibits interfacial stability with Li metals due to the coordinated solvation structure.Lithium nitrate(LiNO_(3))and indium fluoride(InF_(3))are incorporated in the CNE as synergistic co-additives to further stabilize solid-electrolyte interphase(SEI)on Li metals.The resulting electrolyte(CNE+LiNO_(3)/InF_(3))enables stable cycling performance in Li||LiNi_(0.8)Co_(0.1)Mn_(0.1)and 4.9 V-class Li||LiNi_(0.5)Mn_(1.5)O_(4)cells.Notably,the Li||LiNi_(0.5)Mn_(1.5)O_(4)cell maintains its electrochemical activity at high temperature(100℃)and even in flame without fire or explosion.

High-damping and conducting epoxy nanocomposite using both zinc oxide particles and carbon nanofibers

In this study,high-damping and conducting epoxy nanocomposites were developed with carbon nanofibers as conducting materials,and zinc oxide particles as piezoelectric materials.The mechanical and electrical properties,electrical impedance,and loss factors were investigated by uniaxial tensile tests,voltage measurement,impedance measurement,and 3-point bending tests.Two percolation thresholds were found:the percolation threshold of resistivity due to the carbon nanofibers forming conductive networks in the matrix;and the impedance threshold due to the zinc oxide particles acting like electric barriers.A poling treatment of the high-damping and conducting epoxy nanocomposite was considered,and we found that poling treatment helped to make the networks more conductive and to generate voltage from ZnO particles.A high-damping and conducting epoxy nanocomposite with 3 wt%CNF and 10 wt%ZnO exhibited higher loss factor than those of others tested.