Ni-rich layered oxide LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(x≥0.8)is the most promising cathodes for future high energy automotive lithium-ion batteries.However,its application is hindered by the undesirable cycle stability,...Ni-rich layered oxide LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(x≥0.8)is the most promising cathodes for future high energy automotive lithium-ion batteries.However,its application is hindered by the undesirable cycle stability,mainly due to the irreversible structure change at high voltage.Herein,we demonstrate that F substitution with the appropriate amount(1 at%)is capable for improve the electrochemical performance of LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2) cathode significantly.It is revealed that F substitution can reduce cation mixing,stabilize the crystal structure and improve Li transport kinetics.The resulted LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(1.99)F_(0.01)cathode can deliver a high capacity of 194.4 mAh g^(-1) with capacity retention of 95.5%after 100 cycles at 2 C and 165.2 mAh g^(-1) at 5 C.In-situ synchrotron X-ray technique proves that F ions in the cathode materials can suppress the irreversible phase transition from H2 phase to H3 phase in high voltage region by preventing oxygen gliding in a-b planes,ensuring a long-term cycle stability.展开更多
Lithium metal is regarded as the most promising anode material for next generation high energy density lithium batteries due to its high theoretical capacity and lowest potential versus standard hydrogen electrode.How...Lithium metal is regarded as the most promising anode material for next generation high energy density lithium batteries due to its high theoretical capacity and lowest potential versus standard hydrogen electrode.However,lithium dendrite growth and huge volume change during cycling hinder its practical application.It is of great importance to design advanced Li metal anodes to solve these problems.Herein,we report a ZnO-coated Zn foam as the host matrix to pre-store lithium through thermal infusing,achieving a Zn@ZnO foam supported Li composite electrode(LZO).Needlelike ZnO nanofibers grown on the Zn foam greatly increase the surface area and enhance the lithiophilicity of the Zn foam.In situ formed synaptic LiZn layer after lithium infusion can disperse local current density and lower Li diffusion barrier effectively,leading to homogeneous Li deposition behavior,thus suppressing dendrite formation.The porous Zn foam skeleton can accommodate volume variation of the electrode during longterm cycling.Benefiting from these merits,the LZO anode exhibits much better cycle stability and rate capability in both symmetrical and full cells with low voltage hysteresis than the bare Li anode.This work opens a new opportunity in designing high performance composite Li anode for lithium-metal batteries.展开更多
Two major obstacles for the practical application of lithium–sulfur batteries are sluggish redox kinetics and the shuttle effect of lithium polysulfides(LiPSs).Herein,MoN nanolayer-decorated multilayer graphene is fa...Two major obstacles for the practical application of lithium–sulfur batteries are sluggish redox kinetics and the shuttle effect of lithium polysulfides(LiPSs).Herein,MoN nanolayer-decorated multilayer graphene is fabricated via magnetron sputtering then serves as a multifunctional interlayer in Li–S batteries to suppress the shuttle effect and enhance redox kinetics.It is revealed that after the initial discharge process,the MoN layers break up into independent microreaction units consisting of MoN bodies and MoS_(2) edges,forming a heterogeneous composite catalyst in situ.The MoN bodies not only have high sulfur affinity to trap LiPSs but also enhance their redox kinetics.At the same time,the MoS_(2) edge weakens the mobility of LiPSs via the anchoring effect.As a result,Li–S cells using the interlayer present superior cycling stability under a high sulfur loading of 4.8 mg cm^(-2).This work may open a new avenue for developing high-performance Li–S batteries.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52071085,51671058)the Science and Technology Commission of Shanghai Municipality(No.19ZR1404200)。
文摘Ni-rich layered oxide LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(x≥0.8)is the most promising cathodes for future high energy automotive lithium-ion batteries.However,its application is hindered by the undesirable cycle stability,mainly due to the irreversible structure change at high voltage.Herein,we demonstrate that F substitution with the appropriate amount(1 at%)is capable for improve the electrochemical performance of LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2) cathode significantly.It is revealed that F substitution can reduce cation mixing,stabilize the crystal structure and improve Li transport kinetics.The resulted LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(1.99)F_(0.01)cathode can deliver a high capacity of 194.4 mAh g^(-1) with capacity retention of 95.5%after 100 cycles at 2 C and 165.2 mAh g^(-1) at 5 C.In-situ synchrotron X-ray technique proves that F ions in the cathode materials can suppress the irreversible phase transition from H2 phase to H3 phase in high voltage region by preventing oxygen gliding in a-b planes,ensuring a long-term cycle stability.
基金supported by the National Natural Science Foundation of China(No.52071085)Shanghai Aerospace Science and Technology Innovation Fund(No.SAST2020-102).
文摘Lithium metal is regarded as the most promising anode material for next generation high energy density lithium batteries due to its high theoretical capacity and lowest potential versus standard hydrogen electrode.However,lithium dendrite growth and huge volume change during cycling hinder its practical application.It is of great importance to design advanced Li metal anodes to solve these problems.Herein,we report a ZnO-coated Zn foam as the host matrix to pre-store lithium through thermal infusing,achieving a Zn@ZnO foam supported Li composite electrode(LZO).Needlelike ZnO nanofibers grown on the Zn foam greatly increase the surface area and enhance the lithiophilicity of the Zn foam.In situ formed synaptic LiZn layer after lithium infusion can disperse local current density and lower Li diffusion barrier effectively,leading to homogeneous Li deposition behavior,thus suppressing dendrite formation.The porous Zn foam skeleton can accommodate volume variation of the electrode during longterm cycling.Benefiting from these merits,the LZO anode exhibits much better cycle stability and rate capability in both symmetrical and full cells with low voltage hysteresis than the bare Li anode.This work opens a new opportunity in designing high performance composite Li anode for lithium-metal batteries.
基金supported by National Natural Science Foundation of China(No.52071085)Science and Technology Com-mission of Shanghai Municipality(No.19ZR1404200)China Post-doctoral Science Foundation(No.2020M680582).
文摘Two major obstacles for the practical application of lithium–sulfur batteries are sluggish redox kinetics and the shuttle effect of lithium polysulfides(LiPSs).Herein,MoN nanolayer-decorated multilayer graphene is fabricated via magnetron sputtering then serves as a multifunctional interlayer in Li–S batteries to suppress the shuttle effect and enhance redox kinetics.It is revealed that after the initial discharge process,the MoN layers break up into independent microreaction units consisting of MoN bodies and MoS_(2) edges,forming a heterogeneous composite catalyst in situ.The MoN bodies not only have high sulfur affinity to trap LiPSs but also enhance their redox kinetics.At the same time,the MoS_(2) edge weakens the mobility of LiPSs via the anchoring effect.As a result,Li–S cells using the interlayer present superior cycling stability under a high sulfur loading of 4.8 mg cm^(-2).This work may open a new avenue for developing high-performance Li–S batteries.
