The high compacted density LiNi<sub>0.5-x</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>Mg<sub>x</sub>O<sub>2</sub> cathode material for lithium-ion batteries was syn...The high compacted density LiNi<sub>0.5-x</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>Mg<sub>x</sub>O<sub>2</sub> cathode material for lithium-ion batteries was synthesized by high temperature solid-state method, taking the Mg element as a doping element and the spherical Ni<sub>0.5</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> (OH)<sub>2</sub>, Li<sub>2</sub>CO<sub>3</sub> as raw materials. The effects of calcination temperature on the structure and properties of the products were investigated. The structure and morphology of cathode materials powder were analyzed by X-ray diffraction spectroscopy (XRD) and scanning electronmicroscopy (SEM). The electrochemical properties of the cathode materials were studied by charge-discharge test and cyclic properties test. The results show that LiNi<sub>0.4985</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> Mg<sub>0.0015</sub>O<sub>2</sub> cathode material prepared at calcination temperature 930°C has a good layered structure, and the compacted density of the electrode sheet is above 3.68 g/cm<sup>3</sup>. The discharge capacity retention rate is more than 97.5% after 100 cycles at a charge-discharge rate of 1C, displaying a good cyclic performance.展开更多
Although lithium-rich manganese-based(LRM)cathode materials have high capacity(>250 mAh g^(-1))due to their multi-electron redox mechanisms and offer cost advantages due to their high Mn content,challenges remain b...Although lithium-rich manganese-based(LRM)cathode materials have high capacity(>250 mAh g^(-1))due to their multi-electron redox mechanisms and offer cost advantages due to their high Mn content,challenges remain before they can achieve commercialization as replacements for lithium cobalt oxides which have high volumetric energy density.Here,we construct a hierarchically structured LRM cathode,featuring primary micro-bricks and abundant exposure of lithium-ion active transport facets({010}planes).Benefiting from these densely packed bricks and rapid lithium-ion active planes,the hierarchical material achieves an optimal compaction density of 3.4 g cm^(-3) and an ultrahigh volumetric energy density of 3431.0 Wh L^(-1),which is the highest performance level to date.Advanced characterizations,including hard X-ray absorption spectra and wide-angle X-ray scattering spectra,combined with density functional theory calculations,demonstrate that the hierarchical material shows a highly reversible charge compensation process and low-strain structural evolution.In addition,when the material has appropriate Li/Ni intermixing,it is not prone to shearing or sliding along the two-dimensional lithium-ion diffusion planes,which promotes robust architectural stability under high-pressure calendering and long-term cycling.This work should promote the development of advanced cathode materials for rechargeable batteries with high volumetric energy density.展开更多
文摘The high compacted density LiNi<sub>0.5-x</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>Mg<sub>x</sub>O<sub>2</sub> cathode material for lithium-ion batteries was synthesized by high temperature solid-state method, taking the Mg element as a doping element and the spherical Ni<sub>0.5</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> (OH)<sub>2</sub>, Li<sub>2</sub>CO<sub>3</sub> as raw materials. The effects of calcination temperature on the structure and properties of the products were investigated. The structure and morphology of cathode materials powder were analyzed by X-ray diffraction spectroscopy (XRD) and scanning electronmicroscopy (SEM). The electrochemical properties of the cathode materials were studied by charge-discharge test and cyclic properties test. The results show that LiNi<sub>0.4985</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> Mg<sub>0.0015</sub>O<sub>2</sub> cathode material prepared at calcination temperature 930°C has a good layered structure, and the compacted density of the electrode sheet is above 3.68 g/cm<sup>3</sup>. The discharge capacity retention rate is more than 97.5% after 100 cycles at a charge-discharge rate of 1C, displaying a good cyclic performance.
基金sponsored by the National Natural Science Foundation of China(22109010)the National Key R&D Program of China(2021YFC2902905)+3 种基金the Beijing Nova Program,the Chongqing Outstanding Youth Fund(2022NSCQ-JQX3895)the Chongqing Talents Plan for Young Talents(CQYC202005032)the Key Project of Chongqing Technology Innovation and Application Development(2022TIAD-DEX0024)support from the Beijing Institute of Technology Research Fund Program for Young Scholars。
文摘Although lithium-rich manganese-based(LRM)cathode materials have high capacity(>250 mAh g^(-1))due to their multi-electron redox mechanisms and offer cost advantages due to their high Mn content,challenges remain before they can achieve commercialization as replacements for lithium cobalt oxides which have high volumetric energy density.Here,we construct a hierarchically structured LRM cathode,featuring primary micro-bricks and abundant exposure of lithium-ion active transport facets({010}planes).Benefiting from these densely packed bricks and rapid lithium-ion active planes,the hierarchical material achieves an optimal compaction density of 3.4 g cm^(-3) and an ultrahigh volumetric energy density of 3431.0 Wh L^(-1),which is the highest performance level to date.Advanced characterizations,including hard X-ray absorption spectra and wide-angle X-ray scattering spectra,combined with density functional theory calculations,demonstrate that the hierarchical material shows a highly reversible charge compensation process and low-strain structural evolution.In addition,when the material has appropriate Li/Ni intermixing,it is not prone to shearing or sliding along the two-dimensional lithium-ion diffusion planes,which promotes robust architectural stability under high-pressure calendering and long-term cycling.This work should promote the development of advanced cathode materials for rechargeable batteries with high volumetric energy density.
