Improved cyclic performances of LiCoPO4/C cathode materials for high-cell-potential lithium-ion batteries with thiophene as an electrolyte additive

Electrochemical and Magnetic Studies of Li-Deficient Li1-xCo1-xFexPO4Olivine Cathode Compounds

“…If high-voltage cathode is applied to the battery device, the stability of the electrolyte solution at the charged cathode surface is one of the important issues affecting the practical application. The interfacial issues have been studied in many papers, [53][54][55][56][57][58] where some electrolyte additives were effective to form stable SEI layer on the cathode surface in the initial cycle and to reduce the oxidative decomposition of the electrolyte solution on the subsequent cycles. From the view-point of the interfacial properties, the impedance study on the Li 1-x Co 1-x Fe x PO 4 cathode during the chargedischarge cycling in addition to the examination of the electrolyte additives will be our future works.…”

“…One of the reasons for the capacity fading is attributed to the decomposition of the organic electrolyte solution in such a high potential region. Therefore, the surface coating of the cathode active particles and/or the electrolyte additives have been extensively studied in the previous works, [53][54][55][56][57][58] and some improvement have been proposed. In addition to these research works on electrolyte solutions and electrolyte additives, material studies on high-voltage cathode may be required in order to attain the highvoltage battery devices.…”

Effect of lithium difluoro(oxalate)borate (LiDFOB) additive on the performance of high-voltage lithium-ion batteries

“…LiCoPO 4 was prepared via a sol-gel route [31]. A stoichiometric mixture of LiNO 3 , Co(NO 3 ) 2 Á6H 2 O and citric acid was dissolved in deionized water with magnetic stirring, and then (NH 4 ) 2 HPO 4 in stoichiometric ratio was added to the solution and stirred at 85°C to remove the excessive water.…”

“…In this study, LiCoPO 4 , as a representative of highvoltage cathode materials, was prepared [31]. Since LiCoPO 4 always presented poor cyclic stability due to the electrolyte decomposition at high potentials and its intrinsic properties, such as the low electronic conductivity and structural instability during Li deintercalation [32,33], even though various modified strategies were employed [13,[32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51].…”

Additives for Functional Electrolytes of Li-Ion Batteries

“…The additive research for LiCoPO 4 is sparser. Few examples include LiBOB [9], shown to mitigate capacity fade at 3 %, LiDFOB [53], which increased capacity retention at 40 cycles from 34 to 69 % at a 5.1 V cut-off potential, and thiophene [152], which increased capacity retention from 15 to 68 % after 30 cycles. Sharabi et al [111] reported that FEC-containing electrolytes with a small amount (0.5-1 %) of trimethlyboroxine additive allowed for 90 % capacity retention after 100 cycles with a 5.2 V cut-off potential.…”