The isolated inorganic particles within composite polymer electrolytes(CPEs) are not correlated to the Li^(+)transfer network,resulting in the polymer dominating the low ionic conductivity of CPEs.Therefore,we develop...The isolated inorganic particles within composite polymer electrolytes(CPEs) are not correlated to the Li^(+)transfer network,resulting in the polymer dominating the low ionic conductivity of CPEs.Therefore,we developed novel quasi-solid-state CPEs of a Ce-doped Na super ion conductors(NASICON)Na_(1.3+x)Al_(0.3)Ce_(x)Ti_(1.7-x)(PO_(4))_(3)(NCATP) chemically coupled poly(vinylidene fluoride-hexafluoropropylene)(PVDF-HFP)/Li-bis(trifluoromethanes-ulfonyl)imide(LiTFSI) matrix.A strong interaction between Ce^(3+)from NCATP and TFSI-anion from the polymer matrix contributes to the fast Li+transportation at the interface.The PVDF-HFP/NCATP CPEs exhibit an ionic conductivity of 2.16 × 0^(-3) S cm^(-1) and a Li^(+) transference number of 0.88.A symmetric Li/Li cell with NCATP-integrated CPEs at 0.1 mA cm^(-2) presents outstanding cycling stability over 2000 h at 25℃.The quasi-solid-state Li metal batteries of Li/CPEs/LiFePO_(4) at 2 C after 400 cycles and Li/CPEs/LiCoO_(2) at 0.2 C after 120 cycles deliver capacities of 100 and 152 mAh g^(-1) at 25℃,respectively.展开更多
Graphite tailings produced by natural graphite is usually regarded as garbage to be buried underground,which would result in a certain waste of resources.Here,in order to explore the utilization of natural graphite ta...Graphite tailings produced by natural graphite is usually regarded as garbage to be buried underground,which would result in a certain waste of resources.Here,in order to explore the utilization of natural graphite tailings(NGT),a liquid-polyacrylonitrile(LPAN)is used to modify the NGT fragments and aggregate them together to form secondary graphite particles with low surface area and high tap density.Moreover,the modified NGT show much better electrochemical performances than those of original one.When tested in full cells coupled with NMC532 cathode,the material achieves a high rate capability and cycle stability at the cutoff voltage of 4.25 V as well as 4.45 V,which maintains 84.32%capacity retention after 500 cycles at 1 C rate(4.25 V),higher than that of the pristine one(73.65%).The enhanced performances can be attributed to the use of LPAN to create a unique carbon layer upon graphite tailings to reconstruct surface and repair defects,and also to granulate an isotropic structure of secondary graphite particles,which can help to weaken the anisotropy of Li^(+)diffusion pathway and form a uniform,complete and stable solid-electrolyte-interface(SEI)on the surface of primary NGT fragments to promote a fast Li+diffusion and suppress lithium metal dendrites upon charge and discharge.展开更多
In this study,the morphological distribution of Ru on nitrogen-doped graphene(NG)could be rationally regulated via modulating the combination mode between Ru precursor and the zeolite imidazolate framework-8(ZIF-8).Th...In this study,the morphological distribution of Ru on nitrogen-doped graphene(NG)could be rationally regulated via modulating the combination mode between Ru precursor and the zeolite imidazolate framework-8(ZIF-8).The cation exchange and host-guest strategies respectively resulted in two different combination modes between Ru precursor and ZIF-8 anchored on graphene.Following pyrolysis of the above precursors,Ru single-atom sites(SASs)with and without Ru nanoparticles(NPs)were formed selectively on NG(denoted as Ru SASs+NPs/NG and Ru SASs/NG,respectively).Ru SASs+NPs/NG exhibited excellent hydrogen evolution reaction(HER)performance in alkaline solutions(η_(10)=12 mV,12.57 A mg^(-1)_(Ru) at 100 mV),which is much better than Ru SASs/NG.The experimental and theoretical study revealed that Ru SASs could adsorb hydrogen with optimal adsorption strength,while Ru NPs could lower the barrier of water molecule dissociation,and thus Ru SASs and Ru NPs could synergistically promote the catalytic performance of HER in alkaline solutions.展开更多
基金the National Key Research and Development Program of China (No. 2020YFC1909604)the Shenzhen Key Projects of Technological Research (JSGG2020092514 5800001)。
文摘The isolated inorganic particles within composite polymer electrolytes(CPEs) are not correlated to the Li^(+)transfer network,resulting in the polymer dominating the low ionic conductivity of CPEs.Therefore,we developed novel quasi-solid-state CPEs of a Ce-doped Na super ion conductors(NASICON)Na_(1.3+x)Al_(0.3)Ce_(x)Ti_(1.7-x)(PO_(4))_(3)(NCATP) chemically coupled poly(vinylidene fluoride-hexafluoropropylene)(PVDF-HFP)/Li-bis(trifluoromethanes-ulfonyl)imide(LiTFSI) matrix.A strong interaction between Ce^(3+)from NCATP and TFSI-anion from the polymer matrix contributes to the fast Li+transportation at the interface.The PVDF-HFP/NCATP CPEs exhibit an ionic conductivity of 2.16 × 0^(-3) S cm^(-1) and a Li^(+) transference number of 0.88.A symmetric Li/Li cell with NCATP-integrated CPEs at 0.1 mA cm^(-2) presents outstanding cycling stability over 2000 h at 25℃.The quasi-solid-state Li metal batteries of Li/CPEs/LiFePO_(4) at 2 C after 400 cycles and Li/CPEs/LiCoO_(2) at 0.2 C after 120 cycles deliver capacities of 100 and 152 mAh g^(-1) at 25℃,respectively.
基金the financial support of National Key Research and Development Program of China(No.2020YFC1909604)National Natural Science Foundation(NNSF)of China(Nos.52202269,52002248)+1 种基金Shenzhen Key Projects of Technological Research(No.JSGG20200925145800001)and Shenzhen Basic Research Project(Nos.JCYJ20190808145203535,JCYJ20190808163005631)for providing financial support for this work.We are also grateful to the Instrumental Analysis Center of Shenzhen University(Xili Campus)for providing the facilities for our material analyzes。
文摘Graphite tailings produced by natural graphite is usually regarded as garbage to be buried underground,which would result in a certain waste of resources.Here,in order to explore the utilization of natural graphite tailings(NGT),a liquid-polyacrylonitrile(LPAN)is used to modify the NGT fragments and aggregate them together to form secondary graphite particles with low surface area and high tap density.Moreover,the modified NGT show much better electrochemical performances than those of original one.When tested in full cells coupled with NMC532 cathode,the material achieves a high rate capability and cycle stability at the cutoff voltage of 4.25 V as well as 4.45 V,which maintains 84.32%capacity retention after 500 cycles at 1 C rate(4.25 V),higher than that of the pristine one(73.65%).The enhanced performances can be attributed to the use of LPAN to create a unique carbon layer upon graphite tailings to reconstruct surface and repair defects,and also to granulate an isotropic structure of secondary graphite particles,which can help to weaken the anisotropy of Li^(+)diffusion pathway and form a uniform,complete and stable solid-electrolyte-interface(SEI)on the surface of primary NGT fragments to promote a fast Li+diffusion and suppress lithium metal dendrites upon charge and discharge.
基金supported by the National Key Research and Development Program of China(2020YFC1909604)Shenzhen Key Projects of Technological Research(JSGG20200925145800001)+1 种基金Shenzhen Basic Research Project(JCYJ20190808145203535,JCYJ20190808144413257)the Project of Natural Science Foundation of Guangdong Province(2020A1515010379)。
文摘In this study,the morphological distribution of Ru on nitrogen-doped graphene(NG)could be rationally regulated via modulating the combination mode between Ru precursor and the zeolite imidazolate framework-8(ZIF-8).The cation exchange and host-guest strategies respectively resulted in two different combination modes between Ru precursor and ZIF-8 anchored on graphene.Following pyrolysis of the above precursors,Ru single-atom sites(SASs)with and without Ru nanoparticles(NPs)were formed selectively on NG(denoted as Ru SASs+NPs/NG and Ru SASs/NG,respectively).Ru SASs+NPs/NG exhibited excellent hydrogen evolution reaction(HER)performance in alkaline solutions(η_(10)=12 mV,12.57 A mg^(-1)_(Ru) at 100 mV),which is much better than Ru SASs/NG.The experimental and theoretical study revealed that Ru SASs could adsorb hydrogen with optimal adsorption strength,while Ru NPs could lower the barrier of water molecule dissociation,and thus Ru SASs and Ru NPs could synergistically promote the catalytic performance of HER in alkaline solutions.