An adequate wide temperature electrolyte for high nickel ternary cathode is urgent to further develop high energy density batteries.Herein,a comprehensive double-salt local high-concentration sulfolane-based electroly...An adequate wide temperature electrolyte for high nickel ternary cathode is urgent to further develop high energy density batteries.Herein,a comprehensive double-salt local high-concentration sulfolane-based electrolyte(DLi)is proposed with specific sheath structure to build stable interface on the LiNi_(0.8)Co_(0.1)Mn_(0.1O2)(NCM811)cathode at wide operating temperature between−60 and 55℃.Lithium perchlorate(LiClO_(4))in combination with high concentration lithium bis-(trifluoromethanesulfonyl)imide(LiTFSI)strengthens the internal interaction between anion and cation in the solvation structure,increasing Li+transference number of the electrolyte to 0.61.Moreover,the structure and component characteristics of the passive interface layer on NCM811 are modulated,decreasing desolvation energy of Li+ions,benefiting Li+transport dynamics especially at low temperature,and also ensuring the interfacial stability at a wide operating temperature range.As a result,the cathode with DLi exhibits excellent high-temperature storage performance and high capacity retention of 80.5%in 100 cycles at 55℃.Meanwhile,the Li||NCM811 cells can deliver high discharge capacity of 160.1,136.1,and 110.3 mAh·g^(−1)under current density of 0.1 C at−20,−40,and−60℃,maintaining 84.5%,71.8%,and 58.2%of the discharge capacity at 30℃,respectively.Moreover,it enables NCM811 cathode to achieve a reversible capacity of 142.8 mAh·g^(−1)in 200 cycles at−20℃and 0.2 C.Our studies shed light on the molecular strategy of wide operational temperature electrolyte for high nickel ternary cathode.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52172180 and 51872026)the National Key R&D Program of China(No.2018YFB0104300).
文摘An adequate wide temperature electrolyte for high nickel ternary cathode is urgent to further develop high energy density batteries.Herein,a comprehensive double-salt local high-concentration sulfolane-based electrolyte(DLi)is proposed with specific sheath structure to build stable interface on the LiNi_(0.8)Co_(0.1)Mn_(0.1O2)(NCM811)cathode at wide operating temperature between−60 and 55℃.Lithium perchlorate(LiClO_(4))in combination with high concentration lithium bis-(trifluoromethanesulfonyl)imide(LiTFSI)strengthens the internal interaction between anion and cation in the solvation structure,increasing Li+transference number of the electrolyte to 0.61.Moreover,the structure and component characteristics of the passive interface layer on NCM811 are modulated,decreasing desolvation energy of Li+ions,benefiting Li+transport dynamics especially at low temperature,and also ensuring the interfacial stability at a wide operating temperature range.As a result,the cathode with DLi exhibits excellent high-temperature storage performance and high capacity retention of 80.5%in 100 cycles at 55℃.Meanwhile,the Li||NCM811 cells can deliver high discharge capacity of 160.1,136.1,and 110.3 mAh·g^(−1)under current density of 0.1 C at−20,−40,and−60℃,maintaining 84.5%,71.8%,and 58.2%of the discharge capacity at 30℃,respectively.Moreover,it enables NCM811 cathode to achieve a reversible capacity of 142.8 mAh·g^(−1)in 200 cycles at−20℃and 0.2 C.Our studies shed light on the molecular strategy of wide operational temperature electrolyte for high nickel ternary cathode.
