Recent Accepted Papers

 

Towards a highly performing lithium-metal battery with glyme solution and olivine cathode

ChemElectroChem (accepted 27 Feb 2020)  Selected as a Front Cover
Shuangying Wei, Shoichi Inoue, Daniele Di Lecce, Zhenguang Li, Yoichi Tominaga* and Jusef Hassoun*

      High-performance lithium-metal battery is herein achieved by using a glyme-based electrolyte enhanced with LiNO3 additive and LiFePO3 cathode.  An optimal  electrolyte formulation is selected upon detailed analysis of the electrochemical  properties of various solutions formed by dissolving respectively LiFSI, LiTFSI, and LiBETI either in diethylene glycol dimethyl ether or in triethylene glycol dimethyl ether and by adding LiNO3.   Various electrochemical techniques evidence efficient ionic transport, wide stability window, and low reactivity with lithium metal of the solutions.  The best Li/LiFePO4  battery delivers 154 mAh/g at C/3 without any decay after 200 cycles.  Tests within 1C and 5C show initial capacities of about 150 and 140 mAh/g, a retention exceeding 70% upon 500 cycles, and suitable electrode/electrolyte interphases evolution.
 
 

 An alternative composite polymer electrolyte for high performances lithium battery

Journal of Power Sources (accepted 26 Nov 2019)
Vittorio Marangona, Yoichi Tominaga and Jusef Hassoun*

      A composite electrolyte consisting of polyethylene-glycol dimethyl-ether , LiTFSI conducting salt, LiNO3  film-forming additive, and nanometric silica SiO2  filler, is herein obtained by a scalable solvent casting pathway and thoroughly investigated for application in lithium metal polymer battery.  The electrolyte shows an ionic conductivity over 10E-4  S/cm  above 40 °C promoted by repeated heating and cooling, lithium transference number ranging from 0.22 at 45 °C to 0.27 at 70 °C, low interphase resistance and polarization in lithium cell, and an electrochemical stability window extending above 4.4 V.  These optimal features allow the membrane to operate in a lithium cell with LiFePO4  cathode at 50 °C, with specific capacity exceeding 150 mAh/g  and coulombic efficiency approaching 100% over prolonged cycling.
 
 
 

 An end-capped poly(ethylene carbonate)-based concentrated electrolyte for stable cyclability of lithium battery

Electrochimica Acta (11 Feb 2019)
YoichiTominaga*, Yukino Kinno and Kento Kimura

     An end-capped poly(ethylene carbonate) (PEC) having acetate groups (PEC-Ac) was synthesized as a novel polymer matrix for improving the thermal stability and oxidative stability.  A concentrated PEC-Ac electrolyte with 120 mol% of LiFSI had a good conductivity of approximately 10-6 S/cm at 40 °C with an excellent Li transference number ( t+) of 0.8.  Linear sweep voltammetry measurement for the PEC-Ac electrolyte indicates that the oxidation tolerance is more than 5 V, and is greater than that of the original PEC-based electrolyte.  A battery test for the LiFePO4 cell using the PEC-Ac electrolyte was conducted for the first time, finding good capacities ranging from 130 to 160 mAh/g and stable cyclability for more than 60 cycles.