Investigating dopants to improve sintered LiMn2O4 spinel electrode electrochemical cycling limitations

Multicomponent two-layered cathode for thick sintered lithium-ion batteries

“…LiMn 2 O 4 (LMO) active material powder was synthesized according to previous reports. 20,21 100 mM of sodium oxalate (Na 2 C 2 O 4 , Fisher Chemical) and 10 mM of sodium citrate dihydrate (Na 3 C 6 O 7 H 5 Á2H 2 O, Sigma-Aldrich), were dissolved into 400 mL of deionized (DI) water at the same time using a 1000 mL beaker. Within a separate 1000 mL beaker 100 mM of manganese sulfate monohydrate (MnC 2 O 4 Á2H 2 O, Fisher Chemical) was dissolved into 400 mL DI water.…”

“…This behavior has been previously reported for LMO sintered electrodes, and has been attributed to the limited electronic conductivity especially near full lithiation of the LMO material -note that LMO has been reported to be B4 orders of magnitude lower than LCO in electronic conductivity. 5,13,14,20,[40][41][42][43] The capacity from below 3 V for the composite LMO cell was not present at all in the corresponding regions for the sintered electrode cell, although for the sintered full cell system there was only as much Li + available from the anode as was intercalated during charge, whereas with the Li metal anode there was an excess Li + source available to provide the lower potential redox reaction. The sintered LMO electrode also had discharge fade from 106 to 87 mA h g À1 LMO even during the first three cycles at C/50 and down to B71 mA h g À1 LMO in the final (15th) cycle which also was at C/50 (capacity retention at different cycling rates can be found in Fig.…”

“…15,18,19 However, the low electronic conductivity of LMO results in high polarization and limited rate capability in a thick sintered electrode system. 20 Thus, combinations of LMO and LCO will be explored as a multicomponent thick sintered electrode in this report.…”

Microstructure and mechanical properties of electrochemically cycled ice‐templated Li 4 Ti 5 O 12 sintered anodes

“…13 For an equivalent thickness, the absence of inactive components for sintered electrodes has the added benefit of eliminating additional materials from the interstitial regions of the electrode microstructure, which means that relative to composite electrodes sintered electrodes do not have material besides the liquid electrolyte in the porous microstructure to further impede lithium ion transport. 1,5,8,[14][15][16][17] Thus, sintered electrodes in general provide ion transport advantages by eliminating inactive electrode components. In addition, ice-templating further aligns the electrolyteladen pore regions, which can further enhance effective electrode transport properties.…”

“…A limitation at such great thicknesses will always be the substantive ion and electron transport pathways through the electrode microstructure resulting in ionic and electronic cell overpotentials 13 . For an equivalent thickness, the absence of inactive components for sintered electrodes has the added benefit of eliminating additional materials from the interstitial regions of the electrode microstructure, which means that relative to composite electrodes sintered electrodes do not have material besides the liquid electrolyte in the porous microstructure to further impede lithium ion transport 1,5,8,14‐17 . Thus, sintered electrodes in general provide ion transport advantages by eliminating inactive electrode components.…”