Carboxymethyl cellulose grafted with lithium acrylate as anode binder for improving performance of lithium-ion batteries at low temperatures

Background

Due to numerous hydrogen bonding from carboxymethyl cellulose (CMC), CMC as anode binder for Lithium-Ion Batteries (LIBs) performs poor at low temperature. This study designs the less hydrogen bonding forming of anode binder to improve performance of LIBs at low temperatures.

Methods

CMC is grafted with LA via oxa-Michael addition to obtain the product, denoted as CMC-LA. Subsequently, LIBs are constructed by graphite-based anode with CMC-LA and CMC binders, respectively denoted as LIB-CMC-LA and LIB-CMC for coin cells with lithium metal. The data for capacities (C), charge transfer resistance (R_ct), and diffusion coefficients (D_Li+) are respectively calculated from galvanic charge-discharge cycles, electrochemical impedance spectroscopy, and cyclic voltammetry from 25 to -13 °C.

Significant findings

At 25 °C, the data for C, R_ct, and D_Li+ of LIBS-CMC-LA and LIBs-CMC are respectively calculated as 365 mAhg^-1, 15.9 Ω, and 9.84 × 10^–10 cm²s^-1, as well as, 323 mAhg^-1, 17.3Ω, and 2.7 × 10^–10 cm²s^-1. Noticeably, at -10 °C, the data for C, R_ct, and D_Li+ of LIBS-CMC-LA (163mAhg^-1, 613Ω, and 3.46 × 10^–11 cm²s^-1) significantly diverge from those of LIBS-CMC (76 mAhg^-1, 4000Ω, and 7.9 × 10^–13 cm²s^-1), being coincided with the results for the less exothermic area of CMC-LA than CMC from 0 to -20 °C by differential scanning calorimetry analysis.