A cooperative biphasic MoOx–MoPx promoter enables a fast-charging lithium-ion battery

Abstract

The realisation of fast-charging lithium-ion batteries with long cycle lifetimes is hindered by the uncontrollable plating of metallic Li on the graphite anode during high-rate charging. Here we report that surface engineering of graphite with a cooperative biphasic MoOx–MoPx promoter improves the charging rate and suppresses Li plating without compromising energy density. We design and synthesise MoOx–MoPx/graphite via controllable and scalable surface engineering, i.e., the deposition of a MoOx nanolayer on the graphite surface, followed by vapour-induced partial phase transformation of MoOx to MoPx. A variety of analytical studies combined with thermodynamic calculations demonstrate that MoOx effectively mitigates the formation of resistive films on the graphite surface, while MoPx hosts Li+ at relatively high potentials via a fast intercalation reaction and plays a dominant role in lowering the Li+ adsorption energy. The MoOx–MoPx/graphite anode exhibits a fast-charging capability (<10 min charging for 80% of the capacity) and stable cycling performance without any signs of Li plating over 300 cycles when coupled with a LiNi0.6Co0.2Mn0.2O2 cathode. Thus, the developed approach paves the way to the design of advanced anode materials for fast-charging Li-ion batteries.

Gradient porosity electrodes for fast charging lithium-ion batteries

“…2 The concentration polarization, along with the charge-transfer overpotential and ohmic voltage drop, drives the anode potential below the thermodynamic potential of Li metal (<0 V versus Li + /Li), leading to Li plating at the graphite surface. 3 Surficial coating with Al 2 O 3 , 8 MoO x –MoP x , 9 and graphene, 10 as well as treatment with acid and base 11 could effectively reduce the charge-transfer impedance by facilitating Li-ion and/or electron transport at the surface of graphite particles. The ohmic voltage drop could be reduced through the use of electrolytes with a high Li + transference number, 12,13 selection of electrode materials, 14 electrode design with high electronic conductivity 15 and the use of separators with high electrolyte uptake.…”

Honeycomb-like 3D carbon skeletons with embedded phosphorus-rich phosphide nanoparticles as advanced anodes for lithium-ion batteries

“…Compared to the above oxides and sulfide, transition metal phosphides (TMPs) show a lower redox potential, which makes TMPs more suitable for anode materials. 10–16 Among TMPs, iron phosphide materials have attracted increasing attention from researchers due to their environmental friendliness, high natural resources, and low cost. 17–21 Iron phosphide compounds mainly include Fe 3 P, Fe 2 P and FeP.…”

Phosphorus-Doped FeOF Nanoparticle-Based Cathodes for Lithium Storage

“…When using O to partially substitute F in FeF 3 , the ionicity of Fe–F is reduced and the lattice defects are increased, which can integrate the advantages of fluoride and oxide. , However, the rate performance and cycle stability of FeOF are still unsatisfactory because of the low ionic/electronic conductivities, the aggregation of Fe nanoparticles, side reactions of Fe with electrolytes, and the high electronegativity of Fe–F. , Significant efforts have been made to overcome these obstacles, including doping heteroatoms, morphology design, preparation of nanomaterials and composite structures, and so forth. ,, Ion doping has been widely regarded as an effective strategy for enhancing structural stability and improving electronic structure/properties; thus, heteroatom doping may be a straightforward way to improve electrochemical performance. − Especially, non-metal dopants might induce the reconstruction of charge distribution around the sites of the parent material, which may improve the redox activity of the material. − However, the relevant electrochemical mechanism caused by non-metal doping has not been clearly understood. Phosphorus has higher electrical conductivity and the ability to reduce the adsorption energy of Li + to facilitate the interfacial kinetics of Li + intercalation. − Moreover, introducing P into the material can alter the charge balance and endow the material with certain pseudocapacitive properties, thereby improving the rate performance of the material. , The weak M–P bond enhances the electrochemical activity and reversible redox reaction characteristics of electrode materials, which can improve the rate performance of LIBs . Furthermore, the design of nanostructures not only shortens the electron/ion transport distance but also alleviates the volume expansion of the material, thereby effectively improving the reaction kinetics .…”