Lithium-rich Manganese-based Materials Research Articles

Restraining migration and dissolution of transition-metal-ions via functionalized separator for Li-rich Mn-based cathode with high-energy-density

Lithium-rich manganese-based materials (LRMs) are promising cathode for high-energy-density lithium-ion batteries due to their high capacity, low toxicity, and low cost. However, LRMs suffer from serious voltage decay and capacity fade due to continual migration and dissolution of transition metal ions (TMs) during cycling process. Herein, a novel strategy is proposed to inhibit the TMs migration of LRMs through a modified separator by means of functionalized carbon coating layer, which depends on the chemical constraint of the abundant functional groups in the modified super P. In addition, it has been found that the dissolution of TMs can be restrained based on the Le Chatelier’s principle. Moreover, the modified separator owns good wettability toward the electrolyte. As a result, the LRMs cathode with the modified separator delivers a high discharge capacity of 329.93 mA h g−1 at 0.1 C, and achieves good cyclic performance, the enhanced reaction kinetics and low voltage decay. Therefore, this work provides a new idea to promote the comprehensive electrochemical performances of Li-ion batteries with LRMs cathode through a strategy of separator modification.

Enhancing cyclic performance of lithium-rich manganese-based cathode via in-situ co-doping of magnesium and fluorine

Lithium-rich manganese-based materials (LRM) are regarded as promising next-generation commercial cathodes due to their exceptionally high capacities and working voltages. However, lithium-rich manganese-based materials are plagued with inferior cyclic stability and voltage fading, which greatly stifled their commercial transitions. In this work, the dopant F and Mg uniformly distributed lithium-rich manganese-based cathode material is firstly prepared via an in-situ co-precipitation and high-temperature calcination method. The F and Mg co-doped sample can demonstrate excellent cyclic stability (88.56%, after 100 cycles at 1 C), and higher initial discharge and coulombic efficiency by reducing the transition metal (TM) loss and structure stabilization. Thus, this work presents crucial findings in the development of lithium-rich manganese-based materials, which provides a novel doping route and a vital method of cation-anion co-doping to prepare high-performing cathodes.

Reinforced structural stability of Li-rich Mn-based cathodes by constructing multifunctional heterostructure using Nb-based MXenes

Lithium rich manganese based materials (LMR) have promised the likeliestcandidate for next generation lithium-ion battery cathodes owing to its high energy density and low materials cost. However, severe capacity decline and voltage decay hinder their practical application, which is closely concerned with the structure degradation and irreversible oxygen release. Herein, a simple strategy to reinforce the structural stability of LMR materials by constructing heterostructure with Nb-based MXenes (Nb2CTx/Nb4C3Tx) is proposed. A small amount of spinel phase and pseudo-bonding between Nb and O ions as well as extra oxygen vacancies can be induced by the MXenes addition in LMR, effectively inactivating the surface oxygen and suppressing the structure distortion. In addition, MXene can also alleviate the volume change during cycling process and provide additional transport channels for electrons. The ably designed 3 wt% LMR/Nb2CTx cathode presented high initial Coulombic efficiency of 85.6% at 0.1C (vs. 77.4% for the pristine material) and excellent cycling performance with a capacity retention of 83.8% after 200 cycles at 0.5C (vs. 66.6% for the pristine material). This work sheds some light on stabilizing the structure of lithium-rich manganese materials and provides a new idea for the design of other high performance cathode materials.

Advance of lithium ion batteries: The 16th International Meeting on Lithium Batteries

The International Meeting on Lithium Batteries (IMLB), which are held every two years, promotes international collaboration and cooperation and provides a forum for scientists and engineers to discuss fundamentals, innovations and applications in the field of lithium ion batteries. Meanwhile the meeting provides an opportunity for exchanging new ideas and latest results and sharing inspirations. Advance of lithium ion batteries reported in the 16th International Meeting on Lithium Batteries (The IMLB-16, Jeju, Korea, June 17 to 22, 2012) is summarized in this paper. Lithium-rich manganese-based materials, lithium titanate material, 5V spinel materials and nano-silicon anode materials become new hotspots for research. The improvement of silicon anode material and the polymer electrolyte are key areas to further improve safety and energy density of lithium-ion batteries. The lithium-sulfur batteries, lithium-air batteries and super capacitors are research areas of increasing importance.