Oxygenated carbon nitride-based high-energy-density lithium-metal batteries

Lithium(Li)-metal batteries with polymer electrolytes are promising for high-energy-density and safe energy storage applications.However,current polymer electrolytes suffer either low ionic conductivity or inadequate ability to suppress Li dendrite growth at high current densities.This study addresses both issues by incorporating two-dimensional oxygenated carbon nitride(2D OCN)into a polyvinylidene fluoride(PVDF)-based composite polymer electrolyte and modifying the Li anode with OCN.The OCN nanosheets incorporated PVDF electrolyte exhibits a high ionic conductivity(1.6×10^(-4)S cm^(-1)at 25℃)and Li+transference number(0.62),wide electrochemical window(5.3),and excellent fire resistance.Furthermore,the OCN-modified Li anode in situ generates a protective layer of Li_(3)N during cycling,preventing undesirable reactions with PVDF electrolyte and effectively suppressing Li dendrite growth.Symmetric cells using the upgraded PVDF polymer electrolyte and modified Li anode demonstrate long cycling stability over 2500 h at 0.1 mA cm^(-2).Full cells with a high-voltage LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)cathode exhibit high energy density and long-term cycling stability,even at a high loading of 8.2 mg cm^(-2).Incorporating 2D OCN nanosheets into the PVDF-based electrolyte and Li-metal anode provides an effective strategy for achieving safe and high-energy-density Li-metal batteries.

Transparent PVDF-based electrolyte enabled by lipophilic lithium magnesium silicate for solid-state lithium batteries

Solid-state batteries with solid polymer electrolytes are considered the most promising due to their high energy density and safety advantages.However,their development is hindered by the limitations of polymer electrolytes,such as low ionic conductivity,poor mechanical strength and inadequate fire resistance.This study presents a thin polyvinylidene fluoride-based composite solid electrolyte film(25μm incorporating twodimensional modified lipophilic lithium magnesium silicate(LLS)as additives with good dispersibility.The incorporation of LLS promotes grain refinement in polyvinylidene fluoride(PVDF),enhances the densification of electrolyte films,increases the tensile strength to10.42 MPa and the elongation to 251.58%,improves ion transport interfac e,and facilitates uniform deposition of lithium ions.Furthermore,LLS demonstrates strong adsorption ability,promoting the formation of solvated molecules,resulting in high ionic conductivity(2.07×10^(-4)S·cm^(-1)at 30℃)and a stable lithium/electrolyte interface.Symmetric Li//Li cells assembled with the thin composite electrolytes exhibit stable cycling for2000 h at 0.1 mA·cm^(-2)and 0.05 mAh·cm^(-2).Additionally,the LiFePO_(4)//Li battery shows a capacity retention rate of99.9%after 200 cycles at 0.5C and room temperature.