Construction of high-performance Li-rich Mn-based cathodes assisted by a novel water-soluble LiPAA binder

Recently, all types of electrical equipment put forward increasing requirements on the energy density of secondary rechargeable batteries. The low specific capacity of cathode material is the primary factor that restricts the energy density of Li-ion batteries. Li-rich Mn-based cathode materials have the advantages of high specific capacity, high operating voltage, low cost, and environmental friendliness. However, they have the limitations of low first Coulombic efficiency and serious capacity/voltage attenuation. In this work, lithium polyacrylate (LiPAA) has been employed as a water-soluble binder in the electrode to develop a high-performance Li-rich Mn-based cathode. The effect of the LiPAA binder on voltage drop and electrochemical performance of Li[Li 0.2 Co 0.13 Ni 0.13 Mn 0.54 ]O 2 cathode has been examined to reveal the modification mechanism. The results show that carboxyl group (–COOH) in the LiPAA structure can form strong hydrogen bonds with the oxygen atoms in the active material, making the electrode components firmly bonded and thus maintaining the structural stability of the cathode upon cycling. Moreover, the LiPAA binder can effectively inhibit voltage drop of Li[Li 0.2 Co 0.13 Ni 0.13 Mn 0.54 ]O 2 . The discharge voltage of the electrode decreases by only 117 mV after 50 cycles. Green water-soluble LiPAA has broad prospective applications as a binder of electrode materials of secondary batteries.