层状钛硅酸盐化合物作为锂离子电池负极储能材料

锂离子二次电池是手提设备的重要电力来源。近年来,人们为了寻找更新颖更好的锂离子电极材料,开始研究晶形离子交换材料,这种材料具有开放孔道,能够让离子在多孔框架里自由的进出。一种具有层状结构的钛硅酸盐Na-JDF-L1(Na₄Ti₂Si₈O₂₂·4H₂O)经过离子交换后被用作锂离子负极材料。它在循环200次后放电容量保持在364 mAh·g^-1,并且库伦效率约为100%。通过将TiO₂引入Li(Na)-JDF-L1中,有效的提高了材料的首次库伦效率和倍率放电性能。     

ZrO2包覆的层状富锂正极材料0.6Li[Li1/3Mn2/3]O2·0.4LiNi5/12Mn5/12Co1/6O2的电化学性能

采用喷雾干燥法合成了富锂层状氧化物正极材料0.6Li[Li_1/3Mn_2/3]O₂·0.4LiNi_5/12Mn_5/12Co_1/6O₂(简称LNMCO),并使用Zr (CH₃COO)₄进行ZrO₂的包覆改性。TEM测试结果显示纳米级的ZrO₂颗粒附着在LNMCO的表面。包覆质量分数为1.5%的ZrO₂包覆样品的首圈库伦效率和放电比容量有着显著提升,在室温下其首圈库伦效率和放电比容量(电流密度：20 mA·g^-1,电压：2.0~4.8 V)分别为87.2%,279.3 mAh·g^-1,而原样则为75.1%,224.1 mAh·g^-1,循环100圈之后,1.5% ZrO₂包覆样品的放电比容量为248.3 mAh·g^-1,容量保持率为88.9%,高于原样的195.9 mAh·g^-1和87.4%。     

一种作为锂离子电池负极材料的不含溶剂分子的镉配位聚合物

为了开发高能量密度的锂离子电池(LIB),作为LIB电极材料的配位聚合物,已经受到了研究人员的关注。利用CdCl₂、咪唑(Im)和四氟对苯二甲酸(H₂tfbdc)作用合成了一维配位聚合物[Cd (tfbdc)(Im)₄](Cd-TBI),并利用X射线单晶衍射、红外光谱、元素分析和热重实验对Cd-TBI进行了表征。首次考察了它作为LIB负极材料的电化学性能。在电流密度50 mA·g^-1下循环50次后,Cd-TBI电极提供了154 mAh·g^-1的放电比容量,其容量保持率和库仑效率分别为95.7%和99.2%,展示了优良的循环稳定性。在电流密度1 A·g^-1时,Cd-TBI电极仍保持97 mAh·g^-1的可逆比容量。     

锂离子电池正极材料LiNi0.5Co0.4Al0.1O2的合成与性能

采用高温固相法制备了锂离子电池正极材料LiNi_0.5Co_0.4Al_0.1O₂。采用X射线衍射(XRD)、傅里叶红外光谱(FTIR)、扫描电子显微镜(SEM)对材料的结构及表观形貌进行分析。通过恒电流充放电以及循环伏安法进行了电化学性能测试。测试结果表明,充放电电压在3~4.5 V之间,在0.2C倍率下首次放电比容量达到159.9 mAh·g^-1,经50次循环充放电后放电容量为142.6 mAh·g^-1,表现出良好的电化学性能。     

锂离子电池正极材料LiNi0.5Co0.4Al0.1O2的合成与性能

采用高温固相法制备了锂离子电池正极材料LiNi_0.5Co_0.4Al_0.1O₂,采用X射线衍射(XRD)、傅里叶红外光谱(FTIR)、扫描电子显微镜(SEM)对材料的结构及表观形貌进行分析。通过恒电流充放电以及循环伏安法进行了电化学性能测试。测试结果表明,充放电电压在3~4.5V之间,在0.2C倍率下首次放电比容量达到159.9mAh·g^-1,经50次循环充放电后放电容量为142.6mAh·g^-1,表现出良好的电化学性能。     

脉冲激光沉积NiCo2S4薄膜及其电化学特征

采用脉冲激光沉积法制备了NiCo₂S₄薄膜,利用恒流充放电和循环伏安测试研究了NiCo₂S₄薄膜作为锂离子电池负极材料的电化学性能和充放电机理。采用高分辨电子显微镜和选区电子衍射(TEM&SAED)表征了NiCo₂S₄薄膜首次循环过程中的组成与结构变化。恒流充放电测试结果显示NiCo₂S₄薄膜在3 μA·cm^-2的放电电流下,0~3 V(vs Li⁺/Li)范围内,薄膜的首次放电容量为698 mAh·g^-1,经过200次循环之后的放电容量为365 mAh·g^-1;在循环伏安测试中得到了分步反应的可逆氧化还原峰。TEM和SAED分析结果揭示了NiCo₂S₄薄膜与Li的电化学反应机理：首次放电过程中NiCo₂S₄与Li发生转化反应生成了Li₂S、Ni和Co,充电后生成了CoS和NiS复合薄膜。后续循环为CoS和NiS复合薄膜的可逆分解与形成。研究表明NiCo₂S₄是一种有潜在应用价值的锂离子电池负极材料。     

共聚物模板辅助合成高倍率性能多孔Li2FeSiO4@C/CNTs纳米复合正极材料

通过溶胶-凝胶法制备了Li₂FeSiO₄@C/CNTs(LFS@C/CNTs)纳米复合材料,其中三嵌段共聚物P123用作结构导向剂和碳源,碳纳米管作为导电线提高材料的导电性。LFS@C/CNTs不仅具有海绵状纳米孔,能够与电解液充分接触改善锂离子的传输路径,同时由非晶碳和碳纳米管构成的三维桥联导电网络利于电子的快速传递,提高了材料大电流充放电能力和循环稳定性。复合后的LFS@C/CNTs的高倍率性能相比LFS@C明显提高, 当CNTs的掺量为4%,电压窗口为1.5~4.5 V,0.1C电流密度下放电比容量为182 mAh·g^-1。在10C经70次循环后该材料的放电比容量能保持在117 mAh·g^-1,是LFS@C放电比容量(55 mAh·g^-1)的两倍。     

共聚物模板辅助合成高倍率性能多孔Li2FeSiO4@C/CNTs纳米复合正极材料

通过溶胶-凝胶法制备了Li₂FeSiO₄@C/CNTs(LFS@C/CNTs)纳米复合材料,其中三嵌段共聚物P123用作结构导向剂和碳源,碳纳米管作为导电线提高材料的导电性。LFS@C/CNTs不仅具有海绵状纳米孔,能够与电解液充分接触改善锂离子的传输路径,同时由非晶碳和碳纳米管构成的三维桥联导电网络利于电子的快速传递,提高了材料大电流充放电能力和循环稳定性。复合后的LFS@C/CNTs的高倍率性能相比LFS@C明显提高, 当CNTs的掺量为4%,电压窗口为1.5~4.5 V,0.1C电流密度下放电比容量为182 mAh·g^-1。在10C经70次循环后该材料的放电比容量能保持在117 mAh·g^-1,是LFS@C放电比容量(55 mAh·g^-1)的两倍。     

脉冲激光沉积NiCo2S4薄膜及其电化学特征研究

采用脉冲激光沉积法制备了NiCo₂S₄薄膜,利用恒流充放电和循环伏安测试研究了NiCo₂S₄薄膜作为锂离子电池负极材料的电化学性能和充放电机理。采用高分辨电子显微镜和选区电子衍射(TEM&SAED)表征了NiCo₂S₄薄膜首次循环过程中的组成与结构变化。恒流充放电测试结果显示NiCo₂S₄薄膜在3 μA·cm^-2的放电电流下,0~3 V(vs Li⁺/Li)范围内,薄膜的首次放电容量为698 mAh·g^-1,经过200次循环之后的放电容量为365 mAh·g^-1;在循环伏安测试中得到了分步反应的可逆氧化还原峰。TEM和SAED分析结果揭示了NiCo₂S₄薄膜与Li的电化学反应机理：首次放电过程中NiCo₂S₄与Li发生转化反应生成了Li₂S、Ni和Co,充电后生成了CoS和NiS复合薄膜。后续循环为CoS和NiS复合薄膜的可逆分解与形成。研究表明NiCo₂S₄是一种有潜在应用价值的锂离子电池负极材料。     

三维有序大孔Fe2SiO4/SiO2@C锂离子电池负极纳米玻璃陶瓷-碳复合材料制备及电化学性能

以聚苯乙烯（PS）胶晶作为铸模,采用纳米铸造工艺及后续煅烧的方法合成了三维有序大孔Fe₂SiO₄/SiO₂@C纳米玻璃陶瓷锂离子电池负极材料。溶胶-凝胶工艺产生的凝胶在650℃氩气氛炉中煅烧后,Fe₂SiO₄纳米晶体从含铁元素的SiO₂基玻璃中结晶析出,形成由Fe₂SiO₄纳米晶体、铁离子（Fe³⁺）修饰的玻璃态SiO₂和非晶碳组成的三维有序大孔纳米玻璃陶瓷。在50 mA·g^-1电流密度下进行充放电时,其放电容量可达450 mAh·g^-1以上,电流密度增加到250 mA·g^-1时可逆放电容量仍旧稳定地保持在260 mAh·g^-1,而具有同样有序大孔结构和含碳量的非晶态SiO₂@C材料的放电比容量在50 mA·g^-1电流密度时仅为15 mAh·g^-1。这些结果表明,Fe₂SiO₄纳米晶体及Fe³⁺有助于SiO₂基玻璃陶瓷实现可逆储锂过程。     

A Core–Shell Fe/Fe2O3 Nanowire as a High‐Performance Anode Material for Lithium‐Ion Batteries

The preparation of novel one‐dimensional core–shell Fe/Fe₂O₃ nanowires as anodes for high‐performance lithium‐ion batteries (LIBs) is reported. The nanowires are prepared in a facile synthetic process in aqueous solution under ambient conditions with subsequent annealing treatment that could tune the capacity for lithium storage. When this hybrid is used as an anode material for LIBs, the outer Fe₂O₃ shell can act as an electrochemically active material to store and release lithium ions, whereas the highly conductive and inactive Fe core functions as nothing more than an efficient electrical conducting pathway and a remarkable buffer to tolerate volume changes of the electrode materials during the insertion and extraction of lithium ions. The core–shell Fe/Fe₂O₃ nanowire maintains an excellent reversible capacity of over 767 mA h g^?1 at 500 mA g^?1 after 200 cycles with a high average Coulombic efficiency of 98.6 %. Even at 2000 mA g^?1, a stable capacity as high as 538 mA h g^?1 could be obtained. The unique composition and nanostructure of this electrode material contribute to this enhanced electrochemical performance. Due to the ease of large‐scale fabrication and superior electrochemical performance, these hybrid nanowires are promising anode materials for the next generation of high‐performance LIBs.     

Multiple Active Sites: Lithium Storage Mechanism of Cu‐TCNQ as an Anode Material for Lithium‐Ion Batteries

Recently, carboxylate metal‐organic framework (MOF) materials were reported to perform well as anode materials for lithium‐ion batteries (LIBs); however, the presumed lithium storage mechanism of MOFs is controversial. To gain insight into the mechanism of MOFs as anode materials for LIBs, a self‐supported Cu‐TCNQ (TCNQ: 7,7,8,8‐tetracyanoquinodimethane) film was fabricated via an in situ redox routine, and directly used as electrode for LIBs. The first discharge and charge specific capacities of the self‐supported Cu‐TCNQ electrode are 373.4 and 219.4 mAh g^?1, respectively. After 500 cycles, the reversible specific capacity of Cu‐TCNQ reaches 280.9 mAh g^?1 at a current density of 100 mA g^?1. Mutually validated data reveal that the high capacity is ascribed to the multiple‐electron redox conversion of both metal ions and ligands, as well as the reversible insertion and desertion of Li⁺ ions into the benzene rings of ligands. This work raises the expectation for MOFs as electrode materials of LIBs by utilizing multiple active sites and provides new clues for designing improved electrode materials for LIBs.     

Two π-Conjugated Covalent Organic Frameworks with Long-Term Cyclability at High Current Density for Lithium Ion Battery

Organic lithium ion batteries (LIBs) are considered as one of the next-generation green electrochemical energy storage (EES) devices. However, obtaining both high capacity and long-term cyclability is still the bottleneck of organic electrode materials for LIBs because of weak structural and chemical stability and low conductivity. Covalent organic frameworks (COFs) show potential to overcome these problems owing to its good stability and high capacity. Herein, the synthesis and characterization of two π-conjugated COFs, derived from the Schiff-base reaction of 2,4,6-triaminopyrimidne (TM) respectively with 1,4-phthalaldehyde (PA) and 1,3,5-triformylbenzene (TB) by a mechanochemical process are presented. As anode materials for LIBs, the COFs exhibit favorable electrochemical performance with the highest reversible discharge capacities of up to 401.3 and 379.1 mAh g⁻¹ at a high current density (1 A g⁻¹), respectively, and excellent long-term cyclability with 74.8 and 72.7 % capacity retention after 2000 cycles compared to the initial discharge capacities.     

Scalable Synthesis of One-Dimensional Mesoporous ZnMnO3 Nanorods with Ultra-Stable and High Rate Capability for Efficient Lithium Storage

The cost-efficient ZnMnO₃ has attracted increasing attention as a prospective anode candidate for advanced lithium-ion batteries (LIBs) owing to its resourceful abundance, large lithium storage capacity and low operating voltage. However, its practical application is still seriously limited by the modest cycling and rate performances. Herein, a facile design to scalable synthesize unique one-dimensional (1D) mesoporous ZnMnO₃ nanorods (ZMO-NRs) composed of nanoscale particles (≈11 nm) is reported. The 1D mesoporous structure and nanoscale building blocks of the ZMO-NRs effectively promote the transport of ions/electrons, accommodate severe volume changes, and expose more active sites for lithium storage. Benefiting from these appealing structural merits, the obtained ZMO-NRs anode exhibits excellent rate behavior (≈454 mAh g⁻¹ at 2 A g⁻¹) and ultra-long term cyclic performance (≈949.7 mAh g⁻¹ even over 500 cycles at 0.5 A g⁻¹) for efficient lithium storage. Additionally, the LiNi_0.8Co_0.1Mn_0.1O₂//ZMO-NRs full cell presents a practical energy density (≈192.2 Wh kg⁻¹) and impressive cyclability with approximately 91 % capacity retention over 110 cycles. This highlights that the ZMO-NRs product is a highly promising high-rate and stable electrode candidate towards advanced LIBs in electronic devices and sustainable energy storage applications.     

Pushing Up Lithium Storage through Nanostructured Polyazaacene Analogues as Anode

According to the evidence from both theoretical calculations and experimental findings, conjugated ladder polymers containing large π‐conjugated structure, a high number of nitrogen heteroatoms, and a multiring aromatic system, could be an ideal organic anode candidate for lithium‐ion batteries (LIBs). In this report, we demonstrated that the nanostructured polyazaacene analogue poly(1,6‐dihydropyrazino[2,3g]quinoxaline‐2,3,8‐triyl‐7‐(2H)‐ylidene‐7,8‐dimethylidene) (PQL) shows high performance as anode materials in LIBs: high capacity (1750 mAh g^?1, 0.05C), good rate performance (303 mAh g^?1, 5C), and excellent cycle life (1000 cycles), especially at high temperature of 50 °C. Our results suggest nanostructured conjugated ladder polymers could be alternative electrode materials for the practical application of LIBs.     

Needle-like cobalt phosphide arrays grown on carbon fiber cloth as a binder-free electrode with enhanced lithium storage performance

Cobalt phosphide(CoP) is a promising anode candidate for lithium-ion batteries(LIBs) due to its high specific capacity and low working potential.However,the poor cycling stability and rate performance,caused by low electrical conductivity and huge volume variation,impede the further practical application of CoP anode materials.Herein,we report an integrated binder-free electrode featuring needle-like CoP arrays grown on carbon fiber cloth(CC) for efficient lithium storage.The as-prepared CoP/CC electrode integrates the advantages of 1 D needle-like CoP arrays for efficient electrolyte wettability and fast cha rge transpo rtation,and 3 D CC substrate for superior mechanical stability,flexibility and high conductivity.As a result,the CoP/CC electrode delivers an initial specific capacity of 1283 mAh/g and initial Coulombic effeciencies of 85.4%,which are much higher than that of conventional CoP electrode.Notably,the Co P/CC electrode shows outstanding cycling performance up to 400 cycles at 0.5 A/cm² and excellent rate performance with a discharge capacity of 549 mAh/g even at 5 A/cm².This work demonstrates the great potential of integrated CoP/CC hybrid as efficient bind-free and freestanding electrode for LIBs and future flexible electronic devices.     

Layer-By-Layer (LBL) hybrid MOF coating for graphene-based multilayer composite: Synthesis and application as anode for lithium ion batteries

The hybrid anodic materials with high porosity and low charge resistance exhibit high specific capacity and stable cyclic stability for lithium ion battery (LIBs). For this purpose, three-dimensional hollow material, metal organic framework (MOF-199) was coated over the active surface of oxidized derivative of graphene (Graphene oxide, GO), via layer-by-layer (LBL) coating method. Cupric acetate and benzene-1,3,5-tricarboxylic acid [Cu₃(BTC)₂], were alternatively coated on the active surface of GO as an anode material, to enhance the structural diversity and reduce the synergistic effect of insertion and extraction of Li⁺ ions for LIBs. Sharp absorption peaks from 1620 cm⁻¹ to 1360 cm⁻¹ and intense ring bends ∼1000 cm⁻¹ was identified through FTIR. Powder XRD provides the evidence for size reduction of Cu₃(BTC)₂@GO composite (32.6 nm) comparative to GO (43.7 nm). Outcome of EIS analysis shows the charge transfer resistance of simple GO is 2410 Ω, which is 4 times higher than R_ct of Cu₃(BTC)₂@GO composite (590 Ω). Similarly the Warburg impedance co-efficient for simple GO (448.8 Ωs^−1/2) is also higher than A_w of Cu₃(BTC)₂@GO composite (77.64 Ωs^−1/2). The synthesized material show high initial charge/discharge capacity, 1200/1420 mAh/g with 85% Coulombic efficiency and reversible discharge capacity, 1296 mAh/g after 100 cycles at 100 mA/g current density. The 98.9% Coulombic efficiency and 91% retaining capacity of composite at 100th cycle with cyclic stability, provides the phenomenon approach towards the rechargeable LIBs for industrial technology.     

Hybrid Sub-1 nm Nanosheets of Co-assembled MnZnCuOx and Polyoxometalate Clusters as Anodes for Li-ion Batteries

Transition metal oxide (TMO) anode materials in lithium-ion batteries (LIBs) usually suffer from serious volume expansion leading to the pulverization of structures, further giving rise to lower specific capacity and worse cycling stability. Herein, by introducing polyoxometalate (POM) clusters into TMOs and precisely controlling the amount of POMs, the MnZnCuO_x-phosphomolybdic acid hybrid sub-1 nm nanosheets (MZC-PMA HSNSs) anode is successfully fabricated, where the special electron rich structure of POMs is conducive to accelerating the migration of lithium ions on the anode to obtain higher specific capacity, and the non-covalent interactions between POMs and TMOs make the HSNSs possess excellent structural and chemical stability, thus exhibiting outstanding electrochemical performance in LIBs, achieving a high reversible capacity (1157 mAh g⁻¹ at 100 mA g⁻¹) and an admirable long-term cycling stability at low and high current densities.     

Lithium Germanate (Li2GeO3): A High‐Performance Anode Material for Lithium‐Ion Batteries

A simple, cost‐effective, and easily scalable molten salt method for the preparation of Li₂GeO₃ as a new type of high‐performance anode for lithium‐ion batteries is reported. The Li₂GeO₃ exhibits a unique porous architecture consisting of micrometer‐sized clusters (secondary particles) composed of numerous nanoparticles (primary particles) and can be used directly without further carbon coating which is a common exercise for most electrode materials. The new anode displays superior cycling stability with a retained charge capacity of 725 mAh g^?1 after 300 cycles at 50 mA g^?1. The electrode also offers excellent rate capability with a capacity recovery of 810 mAh g^?1 (94 % retention) after 35 cycles of ascending steps of current in the range of 25–800 mA g^?1 and finally back to 25 mA g^?1. This work emphasizes the importance of exploring new electrode materials without carbon coating as carbon‐coated materials demonstrate several drawbacks in full devices. Therefore, this study provides a method and a new type of anode with high reversibility and long cycle stability.