Mn-rich LiFe_(1-x)Mn_(x)PO_(4)(x>0.5),which combines the high operation voltage of LiMnPO_(4)with excellent rate performa nce of LiFePO4,is hindered by its sluggish kinetic properties.Herein,thermodynamic equilibri...Mn-rich LiFe_(1-x)Mn_(x)PO_(4)(x>0.5),which combines the high operation voltage of LiMnPO_(4)with excellent rate performa nce of LiFePO4,is hindered by its sluggish kinetic properties.Herein,thermodynamic equilibrium analysis of Mn^(2+)-Fe^(2+)-Mg^(2+)-C_(2)O_(4)^(2-)-H_(2)O system is used to guide the design and preparation of insitu Mg-doped(Fe_(0.4)Mn_(0.6))_(1-x)Mg_(x)C_(2)O_(4)intermediate,which is then employed as an innovative precursor to synthesize high-performance Mg-doped LiFe_(0.4)Mn_(0.6)PO_(4).It indicates that the metal ions with a high precipitation efficiency and the stoichiometric precursors with uniform element distribution can be achieved under the optimized thermodynamic conditions.Meanwhile,accelerated Li+diffusivity and reduced charge transfer resistance originating from Mg doping are verified by various kinetic characterizations.Benefiting from the contributions of inherited homogeneous element distribution,small particle size,uniform carbon layer coating,enhanced Li+migration ability and structural stability induced by Mg doping,the Li(Fe_(0.4)Mn_(0.6))_(0.97)Mg_(0.03)PO_(4)/C exhibits splendid electrochemical performance.展开更多
硅基材料可用于制备高比容量锂离子电池负极,但其在高电压和高温环境下易发生副反应,而通过在电解液中加入功能添加剂,则可有效缓解上述问题。本文通过在电解液中引入硼酸三乙酯(TEB),结果表明可有效改善4.4 V LiNi_(0.6)Co_(0.1)Mn_(0....硅基材料可用于制备高比容量锂离子电池负极,但其在高电压和高温环境下易发生副反应,而通过在电解液中加入功能添加剂,则可有效缓解上述问题。本文通过在电解液中引入硼酸三乙酯(TEB),结果表明可有效改善4.4 V LiNi_(0.6)Co_(0.1)Mn_(0.3)|石墨@SiO软包电池的问题。与无添加剂电解液电池相比,TEB有效抑制了高温存储产气(产气量减少67.1%)和提高循环性能(25℃,从62.33%提升至90.78%)电池的低温放电容量保持率也提升了2.4%(0.5 C)和8.5%(1 C)。由于TEB加入后,可显著提升高电压LiNi_(0.6)Co_(0.1)Mn_(0.3)|石墨@SiO软包电池的宽温域工作能力,表明它是一种具有使用价值的电解液功能添加剂。展开更多
基金financially supported by the National Natural Science Foundation of China(No.51904250)the China Postdoctoral Science Foundation(No.2021M692254)+2 种基金the Sichuan Science and Technology Program(No.2022YFG0098)the Fundamental Research Funds for the Central Universities(Nos.2021CDSN-02,2022SCU12002,2022CDZG-17,2022CDSN-08,2022CDZG-9)the Hohhot Science and Technology Program(No.2023-Jie Bang Gua Shuai-Gao-3)。
文摘Mn-rich LiFe_(1-x)Mn_(x)PO_(4)(x>0.5),which combines the high operation voltage of LiMnPO_(4)with excellent rate performa nce of LiFePO4,is hindered by its sluggish kinetic properties.Herein,thermodynamic equilibrium analysis of Mn^(2+)-Fe^(2+)-Mg^(2+)-C_(2)O_(4)^(2-)-H_(2)O system is used to guide the design and preparation of insitu Mg-doped(Fe_(0.4)Mn_(0.6))_(1-x)Mg_(x)C_(2)O_(4)intermediate,which is then employed as an innovative precursor to synthesize high-performance Mg-doped LiFe_(0.4)Mn_(0.6)PO_(4).It indicates that the metal ions with a high precipitation efficiency and the stoichiometric precursors with uniform element distribution can be achieved under the optimized thermodynamic conditions.Meanwhile,accelerated Li+diffusivity and reduced charge transfer resistance originating from Mg doping are verified by various kinetic characterizations.Benefiting from the contributions of inherited homogeneous element distribution,small particle size,uniform carbon layer coating,enhanced Li+migration ability and structural stability induced by Mg doping,the Li(Fe_(0.4)Mn_(0.6))_(0.97)Mg_(0.03)PO_(4)/C exhibits splendid electrochemical performance.
文摘硅基材料可用于制备高比容量锂离子电池负极,但其在高电压和高温环境下易发生副反应,而通过在电解液中加入功能添加剂,则可有效缓解上述问题。本文通过在电解液中引入硼酸三乙酯(TEB),结果表明可有效改善4.4 V LiNi_(0.6)Co_(0.1)Mn_(0.3)|石墨@SiO软包电池的问题。与无添加剂电解液电池相比,TEB有效抑制了高温存储产气(产气量减少67.1%)和提高循环性能(25℃,从62.33%提升至90.78%)电池的低温放电容量保持率也提升了2.4%(0.5 C)和8.5%(1 C)。由于TEB加入后,可显著提升高电压LiNi_(0.6)Co_(0.1)Mn_(0.3)|石墨@SiO软包电池的宽温域工作能力,表明它是一种具有使用价值的电解液功能添加剂。
