Construction Of Stable Lithium Metal Anodes For High Energy-density Lithium Metal Batteries

The rapid development of portable electronics and electric vehicles demands high-energy-density and high-power rechargeable batteries.Lithium(Li)metal batteries are the promising next-generation energy storage systems and being revived recently,due to the high theoretical specific capacity(3860m Ah/g)and low electrochemical potential(-3.04 V vs standard hydrogen electrode)of Li metal anodes.However,the development of Li metal anodes is hindered by Li dendrite growth and low Coulombic efficiency(CE)of the Li plating/stripping which cause the safety hazards and short cycling life.Therefore,resolving the fundamental challenges of the Li metal anodes is extremely urgent to enable the practical application of Li metal batteries.In this respect,this study was conducted to establish a lithium metal surface protection mechanism and construct a hybrid lithium alloy structure to realize the optimization of lithium metal anode materials in order to suppress lithium dendrite growth and extend the cycle life of lithium metal batteries.The work has been carried out is shown as follows:1.High interfacial-energy and lithiophilic Janus interphase enables stable lithium metal anodes.A controllable design of an ordered Li F-rich and lithiophilic hybrid Janus interphase(Li F-HJI)is reported using organic fluorination reagent as a functional SEI precursor.The Li F-HJI with a lower crystalline Li F layer and an upper Li organosulfide layer provides high interfacial energy with the Li metal and strong Li-ion affinity,allows homogenous Li-ion distribution,fast and uniform Li-ion transport,and excellent mechanical and passivation properties,enabling stable Li metal anodes under harsh conditions,such as high deposition capacities(6 m Ah/cm~2),current densities(10 m A/cm~2),and rates(5 C).Stable Li F-HJI@Li greatly improves cycling stability and capacity retention(80.1%after 300 cycles)of Li||Li Ni_0.8Co_0.1Mn_0.1O₂full cells at a commercial-level areal capacity(?4.2m Ah/cm~2).Even under a lean-electrolyte condition of 3 g/Ah,80%capacity retention can be maintained after 100 cycles,demonstrating excellent cycling performance under such harsh conditions.2.Regulating lithium deposition behavior by electrokinetic effects in high-zeta-potential BN/zinc-lithium alloy for high-performance lithium metal anodes.We develop a high-zeta-potential BN-doped zinc-lithium alloy(Li-ZB)as an anode to self-drive electrokinetic effects and regulate the lithium deposition behavior.The high-zeta-potential BN in the Li-ZB promotes the electrokinetic surface conduction and electroosmosis within the porous surface framework of Zn-BN formed after the lithium stripping,which in turn greatly enhance the lithium-ion transport kinetics.Uniform Zn distribution in the Li-ZB enables a homogenous lithium nucleation and reduced nucleation barrier.The synergistic effect of electrokinetic effects enhanced lithium-ion transport and regulated lithium nucleation behavior effectively suppresses the lithium dendrite growth at high deposition capacities(6 m Ah/cm~2)and high current densities(10 m Acm~2).The Li-ZB||Li Ni_0.8Co_0.1Mn_0.1O₂full cells exhibit excellent cycling stability and capacity retention,as well as significantly enhanced CE,even under lean-electrolyte conditions(e.g.,3?L/m Ah),indicating the designed Li-ZB anodes show great potential application for the next-generation lithium metal batteries with high energy density.The above results demonstrate new routes to solve the challenges of low CE and poor cycling stability faced by lithium metal anodes,and are of great significance for the development of high-performance,commercially available new rechargeable Li batteries.