The spinel phase LiMnTiO4 as a potential cathode for rechargeable lithium ion batteries

Abstract

Spinel LiMnTiO 4 as the cathode material for Liion batteries has been synthesized by a sol-gel method. The LiMnTiO 4 cathode possesses two voltage plateaus, and exhibits an initial discharge capacity of 203.3 mAh g -1 .After 47 charge-discharge cycles, the capacity retention of the LiMnTiO 4 cathode is 77.5 %, which is much higher than that of LiMn 2 O 4 (47.9 %). Ti substitution can successfully suppress the formation of tetragonal phase during cycling and hence increase the structural stability; however, it decreases the discharge capacity. Multi-walled carbon nanotubes (MWCNTs) were mechanically milled with the pristine LiMnTiO 4 . The as-prepared LiMnTiO 4 /MWCNTs composite electrode exhibits significantly improved electrochemical properties including rate capability and cycling stability, as compared with LiMnTiO 4 .

Lithium intercalation mechanisms and critical role of multi-doping in LiFexMn2−x−yTiyO4 as high-capacity cathode material for lithium-ion batteries

“…The Mn( iii )/Mn( iv ) occurring around 4 V is a single broad signal, indicating a one-step reaction, contrary to what was observed for the undoped spinel, where two couples of sharp redox peaks are obtained between 3.5 and 4.8 V, These peaks can be theoretically attributed to the 2-step transition: one from LiMn 2 O 4 to Li 0.5 Mn III 0.5 Mn IV 1.5 O 4 and the other from Li 0.5 Mn III 0.5 Mn IV 1.5 O 4 to a fully delithiated system (Mn 2 O 4 ). 4 The intensities of both peaks, around 3 and 4 V, decrease coherently with the Mn content in the spinel, as better shown in Fig. S5(I), ESI† reporting the behavior of the 1st cycle-specific capacity as a function of the Li/Mn ratio.…”

“…LFMT powders were synthesized by means of a solÀgel route starting from a mixture of LiCH 3 COOÁ2H 2 O, Mn(NO 3 ) 2 Á4H 2 O, and Fe(NO 3 )Á9H 2 O (Sigma Aldrich) in the proper molar ratios, dissolved in distilled H 2 O under magnetic stirring at room temperature. A solution of Ti(i-OPr) 4 and acetylacetone (acac) (Ti : acac molar ratio of 1 : 1.1) was then added under vigorous stirring to the dissolved precursors. Citric acid was finally added as a gelling agent.…”

“…3 In order to minimize both the disproportionation step and the impact of the J-T distortion, several attempts to dope the spinel were proposed in literature these last decades. [4][5][6][7][8][9][10][11][12][13] A first doping strategy concerns the partial Mn(III) substitution with metals such as Al, Mg, Ni, Cr, Co, Fe, Ti. A second approach was to replace some oxygen with fluorine.…”

Spinel LiMn2−x Si x O4 (x < 1) through Si4+ substitution as a potential cathode material for lithium-ion batteries

“…It is worth noting that there is no appreciable difference in the CV curves of LiMn 2−x Si x O 4 electrode between the second and third cycles, indicating an excellent reversibility as cathode material for Li-ion batteries. An uncertain oxidation peak appears at about 3.80 V in the second and third charging process, but no corresponding reduction peak appears in the subsequent discharging processes, which also appeared in the literature [36]. No explanation has been found for this extra oxidation peak, but it is unlikely to be associated with silicon substitution.…”

Lithium intercalation mechanisms and critical role of multi-doping in LiFexMn2-x-yTiyO4 as high-capacity cathode material for Lithium-ion batteries

“…3 In order to minimize both the disproportionation step and the impact of the J-T distortion, several attempts to dope the spinel were proposed in literature these last decades. [4][5][6][7][8][9][10][11][12][13] A first doping strategy concerns the partial Mn(III) substitution with metals such as Al, Mg, Ni, Cr, Co, Fe, Ti.…”