Single-crystal LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(SC-811),which offers better cycle performance compared to the polycrystalline counterpart,has received great attention.We report herein the synthesis of SC-811 with a gra...Single-crystal LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(SC-811),which offers better cycle performance compared to the polycrystalline counterpart,has received great attention.We report herein the synthesis of SC-811 with a grain size of 2-4μm by washing and reheating method,which compares with conventional polycrystalline LiNi_(0.8)-Co_(0.1)Mn_(0.1)O_(2)(PC-811).The discharge capacity of SC-811 reaches 152.1 mAh·g^(-1)after 100 cycles(86.7%capacity retention)at 1.0 C,which is much better than that of PC-811(130.2 mAh·g^(-1),73.8%capacity retention).By using multiscale characterization,the results unveil that SC-811 can not only improve the reversibility of the H2-H3 phase transitions,suppress the generation of micro-cracks and phase transformations,but also mitigate the undesired side reactions between electrode and electrolyte.Besides,the Li-O bond of SC-811 is longer than that of PC-811,which is conducive to the de-intercalation of Li-ions,thereby enhancing the structural stability.This finding provides an impressive strategy to sustain structural stability and improve the cycling life of Ni-rich layered cathodes.展开更多
Modification of Si anode with various coating matrixes is a promising strategy to resolve the unsta-ble solid electrolyte interphase issues.However,the com-plex preparation process and inherently weak interaction betw...Modification of Si anode with various coating matrixes is a promising strategy to resolve the unsta-ble solid electrolyte interphase issues.However,the com-plex preparation process and inherently weak interaction between Si and other matrixes impede its practical appli-cation.Inspired by the metallurgical process of aluminum,an aluminosilicate matrix was prepared as coating layer on the surface of Si nanoparticles after heat treatment.Si nanoparticles with a uniform native oxide layer were used as seed crystals for the adsorption of aluminum hydroxide.The strong symbiosis and bond between alumina and silica,such as mullite(3Al_(2)O_(3)·2SiO_(2))or kaolin(Al2O_(3)·SiO_(2)·2H_(2)O),provide homogeneous and durable contact coating layer.The as-produced Si/SiO_(2)·Al_(2)O_(3)composite delivers a charge capacity of 1440 mAh·g^(-1)at 100 mA·g^(-1)and remains 879 mAh·g^(-1)at 3 A·g^(-1).After 200 cycles,the capacity retention remains high at 76%.The enhanced properties were ascribed to SiO_(2)·Al_(2)O_(3)syner-gistic composite coating layer,which could hinder the interfacial side chemical reaction and buffer volume change of Si.展开更多
TiNb_(2)O_(7) is an advanced anode material for high-energy density lithium-ion batteries(LIBs) due to its considerable specific capacity and satisfactory safety.However,its rate capability is limited by its poor ioni...TiNb_(2)O_(7) is an advanced anode material for high-energy density lithium-ion batteries(LIBs) due to its considerable specific capacity and satisfactory safety.However,its rate capability is limited by its poor ionic conductivity and electronic conductivity.To solve this problem,TiNb_(2)O_(7) with W^(6+) doping was synthesized by a convenient solid-state method.The doping of W^(6+) will lead to arranging cation mixing and charge compensation.The cation rearrangement creates a new Li-conductive environment for lithiation,resulting in a low-energy barrier and the fast Li^(+)storage/diffusion.The results show that the Li^(+)diffusion coefficient of W_(0.06)Ti_(0.91)Nb_(2)O_(7) is increased by 9.96 times greater than that of TiNb_(2)O_(7).Besides,as the calculation proves,due to the partial reduction of the Nb^(5+)and Ti^(4+) caused by charge compensation,W^(6+)doping results in low charge transfer resistance and excellent electronic conductivity.Moreover,W^(6+) doping accounts for a high pseudocapacitive contribution.At the scan rate of 1 mV·s^(-1),the pseudocapacitive contribution for TiNb_(2)O_(7) is 78%,while that for W_(0.06)Ti_(0.91)Nb_(2)O_(7) increases to 83%.The reversible specific capacity of W_(0.06)Ti_(0.91)Nb_(2)O_(7) after 600 cycles is maintained at 148.90mAh·g^(-1) with a loss of only 16.37% at 10.0C.Also,it delivers a commendable capacity of 161.99 mAh·g^(-1) at20.0C.Even at 30.0C,it still retains a satisfactory capacity of 147.22 mAh·g^(-1),much higher than TiNb_(2)O_(7)(97.49mAh·g^(-1)).Our present study provides ideas for the development of electrode materials for lithium-ion batteries.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51774150 and 51974137)。
文摘Single-crystal LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(SC-811),which offers better cycle performance compared to the polycrystalline counterpart,has received great attention.We report herein the synthesis of SC-811 with a grain size of 2-4μm by washing and reheating method,which compares with conventional polycrystalline LiNi_(0.8)-Co_(0.1)Mn_(0.1)O_(2)(PC-811).The discharge capacity of SC-811 reaches 152.1 mAh·g^(-1)after 100 cycles(86.7%capacity retention)at 1.0 C,which is much better than that of PC-811(130.2 mAh·g^(-1),73.8%capacity retention).By using multiscale characterization,the results unveil that SC-811 can not only improve the reversibility of the H2-H3 phase transitions,suppress the generation of micro-cracks and phase transformations,but also mitigate the undesired side reactions between electrode and electrolyte.Besides,the Li-O bond of SC-811 is longer than that of PC-811,which is conducive to the de-intercalation of Li-ions,thereby enhancing the structural stability.This finding provides an impressive strategy to sustain structural stability and improve the cycling life of Ni-rich layered cathodes.
基金financially supported by the National Natural Science Foundation of China (Nos.52004103, 51974137 and 51774150)China Postdoctoral Science Foundation (No.2020M671361)Jiangsu Postdoctoral Science Foundation (No.2020Z090)
文摘Modification of Si anode with various coating matrixes is a promising strategy to resolve the unsta-ble solid electrolyte interphase issues.However,the com-plex preparation process and inherently weak interaction between Si and other matrixes impede its practical appli-cation.Inspired by the metallurgical process of aluminum,an aluminosilicate matrix was prepared as coating layer on the surface of Si nanoparticles after heat treatment.Si nanoparticles with a uniform native oxide layer were used as seed crystals for the adsorption of aluminum hydroxide.The strong symbiosis and bond between alumina and silica,such as mullite(3Al_(2)O_(3)·2SiO_(2))or kaolin(Al2O_(3)·SiO_(2)·2H_(2)O),provide homogeneous and durable contact coating layer.The as-produced Si/SiO_(2)·Al_(2)O_(3)composite delivers a charge capacity of 1440 mAh·g^(-1)at 100 mA·g^(-1)and remains 879 mAh·g^(-1)at 3 A·g^(-1).After 200 cycles,the capacity retention remains high at 76%.The enhanced properties were ascribed to SiO_(2)·Al_(2)O_(3)syner-gistic composite coating layer,which could hinder the interfacial side chemical reaction and buffer volume change of Si.
基金financially supported by the National Natural Science Foundation of China (Nos. 52274299, 52004103 and 51974137)the Postdoctoral Science Foundation of China (Nos. 2021M691321 and 2020M671361)the Postdoctoral Science Foundation of Jiangsu Province (No. 2020Z090)。
文摘TiNb_(2)O_(7) is an advanced anode material for high-energy density lithium-ion batteries(LIBs) due to its considerable specific capacity and satisfactory safety.However,its rate capability is limited by its poor ionic conductivity and electronic conductivity.To solve this problem,TiNb_(2)O_(7) with W^(6+) doping was synthesized by a convenient solid-state method.The doping of W^(6+) will lead to arranging cation mixing and charge compensation.The cation rearrangement creates a new Li-conductive environment for lithiation,resulting in a low-energy barrier and the fast Li^(+)storage/diffusion.The results show that the Li^(+)diffusion coefficient of W_(0.06)Ti_(0.91)Nb_(2)O_(7) is increased by 9.96 times greater than that of TiNb_(2)O_(7).Besides,as the calculation proves,due to the partial reduction of the Nb^(5+)and Ti^(4+) caused by charge compensation,W^(6+)doping results in low charge transfer resistance and excellent electronic conductivity.Moreover,W^(6+) doping accounts for a high pseudocapacitive contribution.At the scan rate of 1 mV·s^(-1),the pseudocapacitive contribution for TiNb_(2)O_(7) is 78%,while that for W_(0.06)Ti_(0.91)Nb_(2)O_(7) increases to 83%.The reversible specific capacity of W_(0.06)Ti_(0.91)Nb_(2)O_(7) after 600 cycles is maintained at 148.90mAh·g^(-1) with a loss of only 16.37% at 10.0C.Also,it delivers a commendable capacity of 161.99 mAh·g^(-1) at20.0C.Even at 30.0C,it still retains a satisfactory capacity of 147.22 mAh·g^(-1),much higher than TiNb_(2)O_(7)(97.49mAh·g^(-1)).Our present study provides ideas for the development of electrode materials for lithium-ion batteries.
