Highly soluble organic nitrate additives for practical lithium metal batteries

The stability of lithium metal anodes essentially dictates the lifespan of high-energy-density lithium metal batteries.Lithium nitrate(LiNO_(3))is widely recognized as an effective additive to stabilize lithium metal anodes by forming LiN_(x)O_(y)-containing solid electrolyte interphase(SEI).However,its poor solubility in electrolytes,especially ester electrolytes,hinders its applications in lithium metal batteries.Herein,an organic nitrate,isosorbide nitrate(ISDN),is proposed to replace LiNO_(3).ISDNhas a high solubility of 3.3M in ester electrolytes due to the introduction of organic segments in the molecule.The decomposition of ISDN generates LiN_(x)O_(y)-rich SEI,enabling uniform lithium deposition.The lifespan of lithium metal batteries with ISDN significantly increases from 80 to 155 cycles under demanding conditions.Furthermore,a lithium metal pouch cell of 439Whkg^(−1) delivers 50 cycles.This work opens a new avenue to develop additives by molecular modifications for practical lithium metal batteries.

Regulating the electrolyte solvation structure by weakening the solvating power of solvents for stable lithium metal batteries

Rational electrolyte design is essential for stabilizing high-energy-density lithium(Li)metal batteries but is plagued by poor understanding on the effect of electrolyte component properties on solvation structure and interfacial chemistry.Herein,regulating the solvation structure in localized high-concentration electrolytes(LHCE)by weakening the solvating power of solvents is proposed for high-performance LHCE.1,3-dimethoxypropane(DMP)solvent has relatively weak solvating power but maintains the high solubility of Li salts,thus impelling the formation of nanometric aggregates where an anion coordinates to more than two Li-ions(referred to AGG-n)in LHCE.The decomposition of AGG-n increases the Li F content in solid electrolyte interphase(SEI),further enabling uniform Li deposition.The cycle life of Li metal batteries with DMP-based LHCE is 2.1 times(386 cycles)as that of advanced ether-based LHCE under demanding conditions.Furthermore,a Li metal pouch cell of 462Wh kg^(-1)undergoes 58 cycles with the DMP-based LHCE pioneeringly.This work inspires ingenious solvating power regulation to design high-performance electrolytes for practical Li metal batteries.

Bifunctional iron-phtalocyanine metal-organic framework catalyst for ORR, OER and rechargeable zinc-air battery

Exploring non-noble metal and high-activity electrocatalysts through a simple and controllable protocol remains a great challenge for oxygen reduction reaction(ORR)and zinc-air batteries.Herein,we developed a melt polymerization strategy to synthesize iron-polyphthalocyanine(FePPc)metallic-organic frameworks(MOFs)over the carbon black matrix(Fe PPc@CB).Through noncovalentπ-πinteractions,Fe PPc molecules can anchor on carbon matrix,thus facilitating the electron transfer process and stabilizing the systems.Owing to abundant free electrons and atomically MN4 catalytic sites in the macrocycle structure,FePPc@CB exhibits excellent oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalytic activity.The FePPc@CB also delivers excellent performances for liquid and flexible all-solidstate batteries compared to that of commercial Pt/C,making it a promising ORR/OER electrocatalyst.