Rock‐Salt‐Templated Mn₃O₄ Nanoparticles Encapsulated in a Mesoporous 2D Carbon Matrix: A High Rate 2 V Anode for Lithium‐Ion Batteries with Extraordinary Cycling Stability

Abstract

Metal oxide conversion electrodes suffer from low power density and cycling stability desired for high rate lithium‐ion battery (LIB). Herein, we present a method of integrating nanoscale discrete Mn3O4 particles (20 nm) into a two‐dimensional sheet‐like N‐incorporated mesoporous carbon by a simple synthetic protocol using NaCl crystallites as an exo‐template. The encapsulated structure of Mn3O4@C greatly supresses the mechanical stress induced by repeated volumetric expansion/contraction and at the same time, N‐incorporation in the carbon matrix facilitates charge transport. When tested as a 2.0 V LIB anode, Mn3O4@C showed an excellent rate performance (406 mAh g‐1 at 2.5 A g‐1 and 188 mAh g‐1 at 12.5 A g‐1) and outstanding cycling stability (capacity retention of 90% after 10000 cycles at 2.5 A g‐1). Such remarkable performance could be linked to fast charge transportation through the 2D carbon sheets and also, to the encapsulated structure avoiding direct contact with the electrolyte precluding growth of SEI layer upon cycling. Furthermore, a LiFePO4//Mn3O4@C full cell delivers specific capacities of 136 mAh g‐1 and 92 mAh g‐1 (with respect to the mass of cathode) at current densities of 0.25 and 0.5 mA g‐1. The cell shows excellent cycling stability with 76% retention of capacity after 350 cycles demonstrating the practical viability.

Salt‐Assisted Synthesis of 2D Materials

“…Based on the above properties, crystal salt particles have been widely used as templates for the synthesis of nanomaterials. [ 13,47–69 ] The universal procedure comprises coating a precursor solution on the salt template, heat treating in a tube furnace under specific atmosphere, and washing out of the salt template with DI water to obtain 2D materials. [ 48–51,58,59 ] Differing from the CVD and other template methods, STM has the following characteristics: 1) Considering the removal of template, salt templates can be easily removed using water, as most salts are water soluble, whereas graphene and SBA‐15 require treatment with high temperatures or strong acid or base solutions.…”

Salt-assisted synthesis of advanced carbon-based materials for energy-related applications

“…179 Pramanik et al presented the synthesis of a composite comprising nanoscale discrete Mn 3 O 4 particles (20 nm) into a two-dimensional sheet-like N-incorporated mesoporous carbon using NaCl crystallites as an exo-template, which demonstrated excellent performance as anode for a lithium ion battery. 180…”

Efficient energy storage in mustard husk derived porous spherical carbon nanostructures

“…Typical active mass loading was ~6.3 mg based on the mass balance calculation according to our previous work. 6 Fig. 1…”

“…1,3,4 This is so because of the existence of abundant macropores that facilitates mass transport by improving the wettability of the electrode/electrolyte interfaces thereby shortening the diffusion pathways for the charged species and the presence of micro-and/or mesopores that provides a high surface area desired for increased reaction sites. 5,6 In this vein, porous carbon derived from biomass appears to be an attractive prospect for achieving desirable molecular structures and architectures. [7][8][9][10][11][12][13][14] Not only it will provide a green route with a low carbon footprint, but also will provide energy sustainability by the abundance, low cost, and easy processing of the naturally occurring biomass.…”